bump pointer: internal (D-320, concept docs, plan oobe-update-outcome-and-late-start)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.github/scripts/Get-StorageAuthHeaders.ps1

@@ -11,6 +11,7 @@
     Identity comes from whatever `az login` established: the federated GitHub OIDC principal
     in CI (azure/login, subject repo:okieselbach/AutopilotMonitor:ref:refs/heads/main), the
     operator's own account for the local build. No secret is read, stored or passed around.
+    Under GitHub Actions the token is masked in the run log before it is returned.
 
     x-ms-version is MANDATORY here, not decoration: Entra-authorized requests are rejected
     below 2017-11-09, and Table requests without a SAS must carry the header at all. 2021-08-06
@@ -45,6 +46,15 @@ if ($LASTEXITCODE -ne 0 -or [string]::IsNullOrWhiteSpace($token)) {
            'on the table -- a missing role shows up later as HTTP 403 AuthorizationPermissionMismatch.')
 }
 
+# GitHub masks only secrets.* on its own; a token minted at run time is clear text in the
+# (public) run log the moment anything prints it -- an uncaptured call of this script, or
+# Get-Error / Format-List on a failed request, whose TargetObject carries this header.
+# Write-Host, never Write-Output: the output stream is this script's return value. Only
+# under Actions -- anywhere else the line would print the token instead of hiding it.
+if ($env:GITHUB_ACTIONS -eq 'true') {
+    Write-Host "::add-mask::$token"
+}
+
 return @{
     'Authorization' = "Bearer $token"
     'x-ms-version'  = '2021-08-06'

.github/workflows/codeql.yml

@@ -114,7 +114,7 @@ jobs:
           dotnet-version: '10.0.x'
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@b96794f015dfd88f77b49b1c93e0fa7110f94c63 # v4.38.0
+        uses: github/codeql-action/init@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
         with:
           languages: ${{ matrix.language }}
           build-mode: ${{ matrix.build-mode }}
@@ -125,6 +125,6 @@ jobs:
         run: dotnet build AutopilotMonitor.sln --configuration Release
 
       - name: Analyze
-        uses: github/codeql-action/analyze@b96794f015dfd88f77b49b1c93e0fa7110f94c63 # v4.38.0
+        uses: github/codeql-action/analyze@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
         with:
           category: /language:${{ matrix.language }}

.github/workflows/deploy-web.yml

@@ -78,6 +78,23 @@ jobs:
         working-directory: ${{ env.WEB_DIR }}
         run: npm ci
 
+      # Star counter for the GitHub star link (utils/githubStars.ts). Baked into the static HTML
+      # so visitors' browsers never call GitHub; stale until the next web deploy. The token stays
+      # in this step, never in the build. Fail-soft: without a number the link has no counter.
+      - name: Read GitHub star count (fail-soft)
+        id: stars
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+        run: |
+          count=$(gh api "repos/$REPO" --jq .stargazers_count 2>/dev/null || true)
+          if [[ "$count" =~ ^[0-9]+$ ]]; then
+            echo "count=$count" >> "$GITHUB_OUTPUT"
+            echo "GitHub stars: $count"
+          else
+            echo "::warning::GitHub star count unavailable - the star link renders without a counter"
+          fi
+
       # next.config output:'export' -- `next build` writes the static site to out/
       # (prebuild: sync-error-codes, generate-lastmod, generate-version, whats-new).
       - name: Build
@@ -91,6 +108,8 @@ jobs:
           NEXT_PUBLIC_ENTRA_REDIRECT_URI: ${{ vars.NEXT_PUBLIC_ENTRA_REDIRECT_URI }}
           NEXT_PUBLIC_ENTRA_POST_LOGOUT_REDIRECT_URI: ${{ vars.NEXT_PUBLIC_ENTRA_POST_LOGOUT_REDIRECT_URI }}
           NEXT_PUBLIC_API_BASE_URL: ${{ vars.NEXT_PUBLIC_API_BASE_URL }}
+          # Browsers load the live stats through it, and the build reads it once to bake the
+          # numbers of this moment into the landing page's static HTML (lib/platformStats.ts).
           NEXT_PUBLIC_PLATFORM_STATS_MANIFEST_URL: ${{ vars.NEXT_PUBLIC_PLATFORM_STATS_MANIFEST_URL }}
           NEXT_PUBLIC_APPINSIGHTS_CONNECTION_STRING: ${{ secrets.NEXT_PUBLIC_APPINSIGHTS_CONNECTION_STRING }}
           # Build stamp for public/version.json (scripts/generate-version.js in prebuild);
@@ -98,10 +117,15 @@ jobs:
           GITHUB_SHA: ${{ github.sha }}
           # Docs checkout for public/whats-new.json; the prebuild fails in CI without it.
           WHATS_NEW_DOCS_DIR: ${{ github.workspace }}/whats-new-docs
+          # Star counter from the step above; empty when the lookup failed.
+          NEXT_PUBLIC_GITHUB_STARS: ${{ steps.stars.outputs.count }}
         run: |
           npm run build
           test -f out/version.json || { echo "out/version.json missing - export did not run"; exit 1; }
           test -f out/whats-new.json || { echo "out/whats-new.json missing - whats-new prebuild did not run"; exit 1; }
+          # Fail-soft like the star count: browsers still load the stats live; only crawlers and
+          # LLM fetchers, which run no JS, see no numbers until the next deploy.
+          grep -q 'data-stats-snapshot=' out/index.html || echo "::warning::Platform stats were not baked into the landing page (reason in the build log) - crawlers and LLM fetchers see no numbers until the next deploy"
 
       # One archive of the exact bytes that get uploaded, so the attestation has a single subject.
       - name: Package export

rules/analyze/ANALYZE-DEV-004.json

@@ -2,10 +2,10 @@
   "$schema": "../schema/analyze-rule.schema.json",
   "ruleId": "ANALYZE-DEV-004",
   "title": "Windows Update Failed During Enrollment",
-  "description": "Detects a Windows quality/cumulative update that FAILED to install during the OOBE / ESP enrollment window (WindowsUpdateClient EventID 20). A cumulative update failing mid-OOBE is a known cause of enrollment errors and is otherwise invisible in the Intune console.",
+  "description": "Detects a Windows quality/cumulative update that FAILED to install or download during the OOBE / ESP enrollment window (WindowsUpdateClient EventID 20 from the System log, 31 from the Operational channel). A cumulative update failing mid-OOBE is a known cause of enrollment errors and is otherwise invisible in the Intune console.",
   "severity": "high",
   "category": "device",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "enabled": true,
   "evaluateOn": [
     "enrollment_end",
@@ -18,10 +18,14 @@
   "conditions": [
     {
       "signal": "wu_install_failed",
-      "source": "event_type",
+      "source": "event_data",
       "eventType": "windows_update_failed",
+      "dataField": "wuEventId",
       "operator": "exists",
       "value": "",
+      "filterField": "wuPhase",
+      "filterOperator": "in",
+      "filterValue": "install,download",
       "required": true
     },
     {
@@ -31,6 +35,9 @@
       "dataField": "updateTitle",
       "operator": "exists",
       "value": "",
+      "filterField": "wuPhase",
+      "filterOperator": "in",
+      "filterValue": "install,download",
       "required": false
     },
     {
@@ -40,6 +47,9 @@
       "dataField": "hresult",
       "operator": "exists",
       "value": "",
+      "filterField": "wuPhase",
+      "filterOperator": "in",
+      "filterValue": "install,download",
       "required": false
     },
     {
@@ -49,6 +59,9 @@
       "dataField": "hresultSymbol",
       "operator": "exists",
       "value": "",
+      "filterField": "wuPhase",
+      "filterOperator": "in",
+      "filterValue": "install,download",
       "required": false
     },
     {

rules/analyze/ANALYZE-DEV-013.json

@@ -0,0 +1,118 @@
+{
+  "$schema": "../schema/analyze-rule.schema.json",
+  "ruleId": "ANALYZE-DEV-013",
+  "title": "OOBE Quality Update Failed",
+  "description": "Detects that the Windows quality update page at the end of OOBE (Enrollment Status Page setting \"Install Windows quality updates\") reported a failed download or install and recorded no successful install afterwards — the page's own failure names on the oobe_update_page events. Setup usually continues, so the failure is otherwise invisible: the device finishes OOBE without the monthly security update. An OS build change across a restart (os_build_changed) vetoes the finding, and so does the agent's names_capped marker — once the page's event names were capped, a missing success name proves nothing. A downloadInstallFailureHelper entry alone is no failure: updates that installed fine log it too.",
+  "severity": "warning",
+  "category": "device",
+  "version": "1.0.0",
+  "enabled": true,
+  "evaluateOn": [
+    "enrollment_end"
+  ],
+  "trigger": "single",
+  "baseConfidence": 75,
+  "confidenceThreshold": 60,
+  "conditions": [
+    {
+      "signal": "update_failure",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "name",
+      "operator": "in",
+      "value": "SdxWebAppCloudNDUP_processStatusChangeFromHandler_downloadFailedError,SdxWebAppCloudNDUP_processStatusChangeFromHandler_installFailedError,ExpeditedUpdate_commitExpeditionDownloadInstallAsyncFailure",
+      "required": true
+    },
+    {
+      "signal": "no_install_success",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "name",
+      "operator": "not_exists",
+      "value": "",
+      "filterField": "name",
+      "filterOperator": "regex",
+      "filterValue": "installSucceededRebootRequired|commitExpeditionDownloadInstallAsyncSucceeded",
+      "required": true
+    },
+    {
+      "signal": "os_build_unchanged",
+      "source": "event_type",
+      "eventType": "os_build_changed",
+      "operator": "not_exists",
+      "value": "",
+      "required": true
+    },
+    {
+      "signal": "page_names_complete",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "cxhEvent",
+      "operator": "not_exists",
+      "value": "",
+      "filterField": "cxhEvent",
+      "filterOperator": "equals",
+      "filterValue": "names_capped",
+      "required": true
+    },
+    {
+      "signal": "update_page_failed",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "result",
+      "operator": "equals",
+      "value": "fail",
+      "filterField": "page",
+      "filterOperator": "equals",
+      "filterValue": "OobeNDUP",
+      "required": false
+    },
+    {
+      "signal": "update_skipped",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "name",
+      "operator": "regex",
+      "value": "SkipDownloadInstallButtonClicked$",
+      "required": false
+    }
+  ],
+  "confidenceFactors": [
+    {
+      "signal": "update_page_failed",
+      "condition": "exists",
+      "weight": 10
+    }
+  ],
+  "explanation": "The Windows quality update page at the end of OOBE reported `{{update_failure}}`, and no successful install was recorded afterwards. When the download or install of the update fails, the page gives up and setup continues, so the enrollment itself can still succeed — but the device most likely finished OOBE without the monthly security update and installs it only later, through the Windows Update policy that applies after enrollment. Selecting Skip on the page after the failure leads to the same result.",
+  "remediation": [
+    {
+      "title": "Find out why the update failed",
+      "steps": [
+        "Open the oobe_update_page events around the failure in the session timeline: the download progress before it shows how far the download got, and a Skip after it shows that someone chose to continue.",
+        "Check the network path the device uses during OOBE for Windows Update and Delivery Optimization: proxy, TLS inspection and firewall rules for the Windows Update endpoints.",
+        "Compare with other devices: the same failure on many devices of one site points at the network path, on one model at the device, and across the fleet at the update itself."
+      ]
+    },
+    {
+      "title": "Make sure the device gets the update",
+      "steps": [
+        "Verify the device's patch level after enrollment; the update ring assigned to the device installs the missing monthly security update on its normal schedule.",
+        "Where the OOBE quality update keeps failing for one network or device group, decide per Enrollment Status Page profile whether \"Install Windows quality updates\" should stay on."
+      ]
+    }
+  ],
+  "relatedDocs": [
+    {
+      "title": "Microsoft Learn: Install Windows quality updates during OOBE (Enrollment Status Page)",
+      "url": "https://learn.microsoft.com/en-us/intune/device-enrollment/windows/setup-status-page#windows-monthly-security-update-release-details"
+    }
+  ],
+  "markSessionAsFailedDefault": false,
+  "tags": [
+    "device",
+    "windows-update",
+    "oobe",
+    "quality-update"
+  ]
+}

rules/analyze/ANALYZE-DEV-014.json

@@ -0,0 +1,119 @@
+{
+  "$schema": "../schema/analyze-rule.schema.json",
+  "ruleId": "ANALYZE-DEV-014",
+  "title": "OOBE Quality Update Not Offered After an Earlier Failure",
+  "description": "Detects that the Windows quality update page at the end of OOBE found no update to install although the device is out of date, on a device whose update page counts an earlier failed download or install (oobe_update_page: NDUPDownloadInstallPreviousFailureCount above 0, osUpdatesWithNDUPPI false, getDaysOutOfDateSucceeded above 0). No failure and no install success are recorded in this session — a failure in this session is ANALYZE-DEV-013 — and the agent's names_capped marker vetoes the finding, because a missing name proves nothing once the page's names were capped. The device finishes OOBE without the monthly security update.",
+  "severity": "warning",
+  "category": "device",
+  "version": "1.0.0",
+  "enabled": true,
+  "evaluateOn": [
+    "enrollment_end"
+  ],
+  "trigger": "single",
+  "baseConfidence": 75,
+  "confidenceThreshold": 60,
+  "conditions": [
+    {
+      "signal": "previous_failures",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "value",
+      "operator": "gt",
+      "value": "0",
+      "filterField": "name",
+      "filterOperator": "equals",
+      "filterValue": "SdxWebAppCloudNDUP_initialize_NDUPDownloadInstallPreviousFailureCount",
+      "required": true
+    },
+    {
+      "signal": "nothing_offered",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "value",
+      "operator": "equals",
+      "value": "false",
+      "filterField": "name",
+      "filterOperator": "equals",
+      "filterValue": "SdxWebAppCloudNDUP_updateManager_processUpdatesMetadata_osUpdatesWithNDUPPI",
+      "required": true
+    },
+    {
+      "signal": "days_out_of_date",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "value",
+      "operator": "gt",
+      "value": "0",
+      "filterField": "name",
+      "filterOperator": "equals",
+      "filterValue": "ExpeditedUpdate_getDaysOutOfDateSucceeded",
+      "required": true
+    },
+    {
+      "signal": "no_update_failure",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "name",
+      "operator": "not_exists",
+      "value": "",
+      "filterField": "name",
+      "filterOperator": "in",
+      "filterValue": "SdxWebAppCloudNDUP_processStatusChangeFromHandler_downloadFailedError,SdxWebAppCloudNDUP_processStatusChangeFromHandler_installFailedError,ExpeditedUpdate_commitExpeditionDownloadInstallAsyncFailure",
+      "required": true
+    },
+    {
+      "signal": "no_install_success",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "name",
+      "operator": "not_exists",
+      "value": "",
+      "filterField": "name",
+      "filterOperator": "regex",
+      "filterValue": "installSucceededRebootRequired|commitExpeditionDownloadInstallAsyncSucceeded",
+      "required": true
+    },
+    {
+      "signal": "page_names_complete",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "cxhEvent",
+      "operator": "not_exists",
+      "value": "",
+      "filterField": "cxhEvent",
+      "filterOperator": "equals",
+      "filterValue": "names_capped",
+      "required": true
+    }
+  ],
+  "explanation": "The Windows quality update page at the end of OOBE checked for updates and found none to install, although Windows reports the device as {{days_out_of_date}} days out of date. The page's failure counter for this device stands at {{previous_failures}}: an earlier download or install of an OOBE quality update on this device failed. The device finished OOBE without the monthly security update and installs it only later, through the Windows Update policy that applies after enrollment.",
+  "remediation": [
+    {
+      "title": "Check the earlier attempt",
+      "steps": [
+        "Look at the device's earlier enrollment sessions — the failed attempt and its ANALYZE-DEV-013 finding are usually there.",
+        "Verify the device's patch level after enrollment; the update ring assigned to the device installs the missing monthly security update on its normal schedule."
+      ]
+    },
+    {
+      "title": "Reduce how far behind devices start",
+      "steps": [
+        "Devices that start OOBE many months behind need a long update during setup; a current OS image or factory build shortens it and gives a failed attempt less to repeat."
+      ]
+    }
+  ],
+  "relatedDocs": [
+    {
+      "title": "Microsoft Learn: Install Windows quality updates during OOBE (Enrollment Status Page)",
+      "url": "https://learn.microsoft.com/en-us/intune/device-enrollment/windows/setup-status-page#windows-monthly-security-update-release-details"
+    }
+  ],
+  "markSessionAsFailedDefault": false,
+  "tags": [
+    "device",
+    "windows-update",
+    "oobe",
+    "quality-update"
+  ]
+}

rules/analyze/ANALYZE-DEV-015.json

@@ -0,0 +1,117 @@
+{
+  "$schema": "../schema/analyze-rule.schema.json",
+  "ruleId": "ANALYZE-DEV-015",
+  "title": "OOBE Update Check Ended Without a Result",
+  "description": "Detects that the Windows quality update page at the end of OOBE started its Windows Update scan but ended without a scan result (oobe_update_page: startWUScanStartedSuccedded, an OobeNDUP stop and no ExpeditedUpdate_getUpdateResults name), on a device that is out of date and allowed to update. In the observed sessions the page ended two minutes after the scan started, on devices more than a year behind. The device finishes OOBE without the monthly security update. The agent's names_capped marker vetoes the finding: once the page's event names were capped, a missing scan result proves nothing.",
+  "severity": "warning",
+  "category": "device",
+  "version": "1.0.0",
+  "enabled": true,
+  "evaluateOn": [
+    "enrollment_end"
+  ],
+  "trigger": "single",
+  "baseConfidence": 75,
+  "confidenceThreshold": 60,
+  "conditions": [
+    {
+      "signal": "update_allowed",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "value",
+      "operator": "equals",
+      "value": "true",
+      "filterField": "name",
+      "filterOperator": "equals",
+      "filterValue": "ExpeditedUpdate_isNDUPAllowedByCSPSucceeded",
+      "required": true
+    },
+    {
+      "signal": "scan_started",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "name",
+      "operator": "equals",
+      "value": "ExpeditedUpdate_startWUScanStartedSuccedded",
+      "required": true
+    },
+    {
+      "signal": "no_scan_result",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "name",
+      "operator": "not_exists",
+      "value": "",
+      "filterField": "name",
+      "filterOperator": "regex",
+      "filterValue": "^ExpeditedUpdate_getUpdateResults",
+      "required": true
+    },
+    {
+      "signal": "update_page_ended",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "cxhEvent",
+      "operator": "equals",
+      "value": "page_stopped",
+      "filterField": "page",
+      "filterOperator": "equals",
+      "filterValue": "OobeNDUP",
+      "required": true
+    },
+    {
+      "signal": "days_out_of_date",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "value",
+      "operator": "gt",
+      "value": "0",
+      "filterField": "name",
+      "filterOperator": "equals",
+      "filterValue": "ExpeditedUpdate_getDaysOutOfDateSucceeded",
+      "required": true
+    },
+    {
+      "signal": "page_names_complete",
+      "source": "event_data",
+      "eventType": "oobe_update_page",
+      "dataField": "cxhEvent",
+      "operator": "not_exists",
+      "value": "",
+      "filterField": "cxhEvent",
+      "filterOperator": "equals",
+      "filterValue": "names_capped",
+      "required": true
+    }
+  ],
+  "explanation": "The Windows quality update page at the end of OOBE started a Windows Update scan, but no scan result arrived before the page ended. The device is {{days_out_of_date}} days out of date, so an update was due — the device finished OOBE without the monthly security update and installs it only later, through the Windows Update policy that applies after enrollment. The page waits only a short time for the scan (two minutes in the observed sessions): a scan that takes longer, or cannot reach Windows Update, ends the page without an update.",
+  "remediation": [
+    {
+      "title": "Check the path to Windows Update during OOBE",
+      "steps": [
+        "Verify that devices in OOBE reach the Windows Update service: proxy, TLS inspection and firewall rules for the Windows Update endpoints.",
+        "Check whether an update policy applied during the Enrollment Status Page points the scan at another source, such as WSUS."
+      ]
+    },
+    {
+      "title": "Shorten the scan",
+      "steps": [
+        "Devices far behind scan longer; a current OS image or factory build keeps the OOBE scan short.",
+        "Verify the device's patch level after enrollment; the update ring assigned to the device installs the missing monthly security update on its normal schedule."
+      ]
+    }
+  ],
+  "relatedDocs": [
+    {
+      "title": "Microsoft Learn: Install Windows quality updates during OOBE (Enrollment Status Page)",
+      "url": "https://learn.microsoft.com/en-us/intune/device-enrollment/windows/setup-status-page#windows-monthly-security-update-release-details"
+    }
+  ],
+  "markSessionAsFailedDefault": false,
+  "tags": [
+    "device",
+    "windows-update",
+    "oobe",
+    "quality-update"
+  ]
+}

rules/dist/analyze-rules.json

@@ -1385,10 +1385,10 @@
     {
       "ruleId": "ANALYZE-DEV-004",
       "title": "Windows Update Failed During Enrollment",
-      "description": "Detects a Windows quality/cumulative update that FAILED to install during the OOBE / ESP enrollment window (WindowsUpdateClient EventID 20). A cumulative update failing mid-OOBE is a known cause of enrollment errors and is otherwise invisible in the Intune console.",
+      "description": "Detects a Windows quality/cumulative update that FAILED to install or download during the OOBE / ESP enrollment window (WindowsUpdateClient EventID 20 from the System log, 31 from the Operational channel). A cumulative update failing mid-OOBE is a known cause of enrollment errors and is otherwise invisible in the Intune console.",
       "severity": "high",
       "category": "device",
-      "version": "1.1.0",
+      "version": "1.2.0",
       "enabled": true,
       "evaluateOn": [
         "enrollment_end",
@@ -1401,10 +1401,14 @@
       "conditions": [
         {
           "signal": "wu_install_failed",
-          "source": "event_type",
+          "source": "event_data",
           "eventType": "windows_update_failed",
+          "dataField": "wuEventId",
           "operator": "exists",
           "value": "",
+          "filterField": "wuPhase",
+          "filterOperator": "in",
+          "filterValue": "install,download",
           "required": true
         },
         {
@@ -1414,6 +1418,9 @@
           "dataField": "updateTitle",
           "operator": "exists",
           "value": "",
+          "filterField": "wuPhase",
+          "filterOperator": "in",
+          "filterValue": "install,download",
           "required": false
         },
         {
@@ -1423,6 +1430,9 @@
           "dataField": "hresult",
           "operator": "exists",
           "value": "",
+          "filterField": "wuPhase",
+          "filterOperator": "in",
+          "filterValue": "install,download",
           "required": false
         },
         {
@@ -1432,6 +1442,9 @@
           "dataField": "hresultSymbol",
           "operator": "exists",
           "value": "",
+          "filterField": "wuPhase",
+          "filterOperator": "in",
+          "filterValue": "install,download",
           "required": false
         },
         {
@@ -1917,6 +1930,357 @@
         "environment"
       ]
     },
+    {
+      "ruleId": "ANALYZE-DEV-013",
+      "title": "OOBE Quality Update Failed",
+      "description": "Detects that the Windows quality update page at the end of OOBE (Enrollment Status Page setting \"Install Windows quality updates\") reported a failed download or install and recorded no successful install afterwards — the page's own failure names on the oobe_update_page events. Setup usually continues, so the failure is otherwise invisible: the device finishes OOBE without the monthly security update. An OS build change across a restart (os_build_changed) vetoes the finding, and so does the agent's names_capped marker — once the page's event names were capped, a missing success name proves nothing. A downloadInstallFailureHelper entry alone is no failure: updates that installed fine log it too.",
+      "severity": "warning",
+      "category": "device",
+      "version": "1.0.0",
+      "enabled": true,
+      "evaluateOn": [
+        "enrollment_end"
+      ],
+      "trigger": "single",
+      "baseConfidence": 75,
+      "confidenceThreshold": 60,
+      "conditions": [
+        {
+          "signal": "update_failure",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "name",
+          "operator": "in",
+          "value": "SdxWebAppCloudNDUP_processStatusChangeFromHandler_downloadFailedError,SdxWebAppCloudNDUP_processStatusChangeFromHandler_installFailedError,ExpeditedUpdate_commitExpeditionDownloadInstallAsyncFailure",
+          "required": true
+        },
+        {
+          "signal": "no_install_success",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "name",
+          "operator": "not_exists",
+          "value": "",
+          "filterField": "name",
+          "filterOperator": "regex",
+          "filterValue": "installSucceededRebootRequired|commitExpeditionDownloadInstallAsyncSucceeded",
+          "required": true
+        },
+        {
+          "signal": "os_build_unchanged",
+          "source": "event_type",
+          "eventType": "os_build_changed",
+          "operator": "not_exists",
+          "value": "",
+          "required": true
+        },
+        {
+          "signal": "page_names_complete",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "cxhEvent",
+          "operator": "not_exists",
+          "value": "",
+          "filterField": "cxhEvent",
+          "filterOperator": "equals",
+          "filterValue": "names_capped",
+          "required": true
+        },
+        {
+          "signal": "update_page_failed",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "result",
+          "operator": "equals",
+          "value": "fail",
+          "filterField": "page",
+          "filterOperator": "equals",
+          "filterValue": "OobeNDUP",
+          "required": false
+        },
+        {
+          "signal": "update_skipped",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "name",
+          "operator": "regex",
+          "value": "SkipDownloadInstallButtonClicked$",
+          "required": false
+        }
+      ],
+      "confidenceFactors": [
+        {
+          "signal": "update_page_failed",
+          "condition": "exists",
+          "weight": 10
+        }
+      ],
+      "explanation": "The Windows quality update page at the end of OOBE reported `{{update_failure}}`, and no successful install was recorded afterwards. When the download or install of the update fails, the page gives up and setup continues, so the enrollment itself can still succeed — but the device most likely finished OOBE without the monthly security update and installs it only later, through the Windows Update policy that applies after enrollment. Selecting Skip on the page after the failure leads to the same result.",
+      "remediation": [
+        {
+          "title": "Find out why the update failed",
+          "steps": [
+            "Open the oobe_update_page events around the failure in the session timeline: the download progress before it shows how far the download got, and a Skip after it shows that someone chose to continue.",
+            "Check the network path the device uses during OOBE for Windows Update and Delivery Optimization: proxy, TLS inspection and firewall rules for the Windows Update endpoints.",
+            "Compare with other devices: the same failure on many devices of one site points at the network path, on one model at the device, and across the fleet at the update itself."
+          ]
+        },
+        {
+          "title": "Make sure the device gets the update",
+          "steps": [
+            "Verify the device's patch level after enrollment; the update ring assigned to the device installs the missing monthly security update on its normal schedule.",
+            "Where the OOBE quality update keeps failing for one network or device group, decide per Enrollment Status Page profile whether \"Install Windows quality updates\" should stay on."
+          ]
+        }
+      ],
+      "relatedDocs": [
+        {
+          "title": "Microsoft Learn: Install Windows quality updates during OOBE (Enrollment Status Page)",
+          "url": "https://learn.microsoft.com/en-us/intune/device-enrollment/windows/setup-status-page#windows-monthly-security-update-release-details"
+        }
+      ],
+      "markSessionAsFailedDefault": false,
+      "tags": [
+        "device",
+        "windows-update",
+        "oobe",
+        "quality-update"
+      ]
+    },
+    {
+      "ruleId": "ANALYZE-DEV-014",
+      "title": "OOBE Quality Update Not Offered After an Earlier Failure",
+      "description": "Detects that the Windows quality update page at the end of OOBE found no update to install although the device is out of date, on a device whose update page counts an earlier failed download or install (oobe_update_page: NDUPDownloadInstallPreviousFailureCount above 0, osUpdatesWithNDUPPI false, getDaysOutOfDateSucceeded above 0). No failure and no install success are recorded in this session — a failure in this session is ANALYZE-DEV-013 — and the agent's names_capped marker vetoes the finding, because a missing name proves nothing once the page's names were capped. The device finishes OOBE without the monthly security update.",
+      "severity": "warning",
+      "category": "device",
+      "version": "1.0.0",
+      "enabled": true,
+      "evaluateOn": [
+        "enrollment_end"
+      ],
+      "trigger": "single",
+      "baseConfidence": 75,
+      "confidenceThreshold": 60,
+      "conditions": [
+        {
+          "signal": "previous_failures",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "value",
+          "operator": "gt",
+          "value": "0",
+          "filterField": "name",
+          "filterOperator": "equals",
+          "filterValue": "SdxWebAppCloudNDUP_initialize_NDUPDownloadInstallPreviousFailureCount",
+          "required": true
+        },
+        {
+          "signal": "nothing_offered",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "value",
+          "operator": "equals",
+          "value": "false",
+          "filterField": "name",
+          "filterOperator": "equals",
+          "filterValue": "SdxWebAppCloudNDUP_updateManager_processUpdatesMetadata_osUpdatesWithNDUPPI",
+          "required": true
+        },
+        {
+          "signal": "days_out_of_date",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "value",
+          "operator": "gt",
+          "value": "0",
+          "filterField": "name",
+          "filterOperator": "equals",
+          "filterValue": "ExpeditedUpdate_getDaysOutOfDateSucceeded",
+          "required": true
+        },
+        {
+          "signal": "no_update_failure",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "name",
+          "operator": "not_exists",
+          "value": "",
+          "filterField": "name",
+          "filterOperator": "in",
+          "filterValue": "SdxWebAppCloudNDUP_processStatusChangeFromHandler_downloadFailedError,SdxWebAppCloudNDUP_processStatusChangeFromHandler_installFailedError,ExpeditedUpdate_commitExpeditionDownloadInstallAsyncFailure",
+          "required": true
+        },
+        {
+          "signal": "no_install_success",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "name",
+          "operator": "not_exists",
+          "value": "",
+          "filterField": "name",
+          "filterOperator": "regex",
+          "filterValue": "installSucceededRebootRequired|commitExpeditionDownloadInstallAsyncSucceeded",
+          "required": true
+        },
+        {
+          "signal": "page_names_complete",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "cxhEvent",
+          "operator": "not_exists",
+          "value": "",
+          "filterField": "cxhEvent",
+          "filterOperator": "equals",
+          "filterValue": "names_capped",
+          "required": true
+        }
+      ],
+      "explanation": "The Windows quality update page at the end of OOBE checked for updates and found none to install, although Windows reports the device as {{days_out_of_date}} days out of date. The page's failure counter for this device stands at {{previous_failures}}: an earlier download or install of an OOBE quality update on this device failed. The device finished OOBE without the monthly security update and installs it only later, through the Windows Update policy that applies after enrollment.",
+      "remediation": [
+        {
+          "title": "Check the earlier attempt",
+          "steps": [
+            "Look at the device's earlier enrollment sessions — the failed attempt and its ANALYZE-DEV-013 finding are usually there.",
+            "Verify the device's patch level after enrollment; the update ring assigned to the device installs the missing monthly security update on its normal schedule."
+          ]
+        },
+        {
+          "title": "Reduce how far behind devices start",
+          "steps": [
+            "Devices that start OOBE many months behind need a long update during setup; a current OS image or factory build shortens it and gives a failed attempt less to repeat."
+          ]
+        }
+      ],
+      "relatedDocs": [
+        {
+          "title": "Microsoft Learn: Install Windows quality updates during OOBE (Enrollment Status Page)",
+          "url": "https://learn.microsoft.com/en-us/intune/device-enrollment/windows/setup-status-page#windows-monthly-security-update-release-details"
+        }
+      ],
+      "markSessionAsFailedDefault": false,
+      "tags": [
+        "device",
+        "windows-update",
+        "oobe",
+        "quality-update"
+      ]
+    },
+    {
+      "ruleId": "ANALYZE-DEV-015",
+      "title": "OOBE Update Check Ended Without a Result",
+      "description": "Detects that the Windows quality update page at the end of OOBE started its Windows Update scan but ended without a scan result (oobe_update_page: startWUScanStartedSuccedded, an OobeNDUP stop and no ExpeditedUpdate_getUpdateResults name), on a device that is out of date and allowed to update. In the observed sessions the page ended two minutes after the scan started, on devices more than a year behind. The device finishes OOBE without the monthly security update. The agent's names_capped marker vetoes the finding: once the page's event names were capped, a missing scan result proves nothing.",
+      "severity": "warning",
+      "category": "device",
+      "version": "1.0.0",
+      "enabled": true,
+      "evaluateOn": [
+        "enrollment_end"
+      ],
+      "trigger": "single",
+      "baseConfidence": 75,
+      "confidenceThreshold": 60,
+      "conditions": [
+        {
+          "signal": "update_allowed",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "value",
+          "operator": "equals",
+          "value": "true",
+          "filterField": "name",
+          "filterOperator": "equals",
+          "filterValue": "ExpeditedUpdate_isNDUPAllowedByCSPSucceeded",
+          "required": true
+        },
+        {
+          "signal": "scan_started",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "name",
+          "operator": "equals",
+          "value": "ExpeditedUpdate_startWUScanStartedSuccedded",
+          "required": true
+        },
+        {
+          "signal": "no_scan_result",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "name",
+          "operator": "not_exists",
+          "value": "",
+          "filterField": "name",
+          "filterOperator": "regex",
+          "filterValue": "^ExpeditedUpdate_getUpdateResults",
+          "required": true
+        },
+        {
+          "signal": "update_page_ended",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "cxhEvent",
+          "operator": "equals",
+          "value": "page_stopped",
+          "filterField": "page",
+          "filterOperator": "equals",
+          "filterValue": "OobeNDUP",
+          "required": true
+        },
+        {
+          "signal": "days_out_of_date",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "value",
+          "operator": "gt",
+          "value": "0",
+          "filterField": "name",
+          "filterOperator": "equals",
+          "filterValue": "ExpeditedUpdate_getDaysOutOfDateSucceeded",
+          "required": true
+        },
+        {
+          "signal": "page_names_complete",
+          "source": "event_data",
+          "eventType": "oobe_update_page",
+          "dataField": "cxhEvent",
+          "operator": "not_exists",
+          "value": "",
+          "filterField": "cxhEvent",
+          "filterOperator": "equals",
+          "filterValue": "names_capped",
+          "required": true
+        }
+      ],
+      "explanation": "The Windows quality update page at the end of OOBE started a Windows Update scan, but no scan result arrived before the page ended. The device is {{days_out_of_date}} days out of date, so an update was due — the device finished OOBE without the monthly security update and installs it only later, through the Windows Update policy that applies after enrollment. The page waits only a short time for the scan (two minutes in the observed sessions): a scan that takes longer, or cannot reach Windows Update, ends the page without an update.",
+      "remediation": [
+        {
+          "title": "Check the path to Windows Update during OOBE",
+          "steps": [
+            "Verify that devices in OOBE reach the Windows Update service: proxy, TLS inspection and firewall rules for the Windows Update endpoints.",
+            "Check whether an update policy applied during the Enrollment Status Page points the scan at another source, such as WSUS."
+          ]
+        },
+        {
+          "title": "Shorten the scan",
+          "steps": [
+            "Devices far behind scan longer; a current OS image or factory build keeps the OOBE scan short.",
+            "Verify the device's patch level after enrollment; the update ring assigned to the device installs the missing monthly security update on its normal schedule."
+          ]
+        }
+      ],
+      "relatedDocs": [
+        {
+          "title": "Microsoft Learn: Install Windows quality updates during OOBE (Enrollment Status Page)",
+          "url": "https://learn.microsoft.com/en-us/intune/device-enrollment/windows/setup-status-page#windows-monthly-security-update-release-details"
+        }
+      ],
+      "markSessionAsFailedDefault": false,
+      "tags": [
+        "device",
+        "windows-update",
+        "oobe",
+        "quality-update"
+      ]
+    },
     {
       "ruleId": "ANALYZE-ENRL-001",
       "title": "Enrollment Failed",

rules/dist/ime-log-patterns.json

@@ -203,7 +203,7 @@
       "category": "currentPhase",
       "pattern": "^\\[DO TEL\\] = (?<doTelJson>\\{.*\\})",
       "action": "updateDoTelemetry",
-      "description": "Captures Delivery Optimization telemetry JSON after a DO download completes. Contains file size, peer caching stats, download mode, and duration. IME removed the [DO TEL] emitter in 1.104 (absent in 1.104.102.0 and 1.105.103.0 decompiles, present in 1.97.107.0); kept while 1.101/1.103 devices are in the fleet — retire once those versions are gone.",
+      "description": "Captures Delivery Optimization telemetry JSON after a DO download completes. Contains file size, peer caching stats, download mode, and duration. IME removed the [DO TEL] emitter in 1.104 (absent from the 1.104.102.0 and 1.105.103.0 builds, present in 1.97.107.0); kept while 1.101/1.103 devices are in the fleet — retire once those versions are gone.",
       "enabled": true
     },
     {
@@ -584,7 +584,7 @@
       "category": "always",
       "pattern": "^Failed to get AAD token\\..*?errorCode = (?<errorCode>.*?)$",
       "action": "imeTokenFailure",
-      "description": "IME token acquisition failure ('Failed to get AAD token. len = N using client id ... and resource id ..., errorCode = N', IntuneTokenManager, IntuneManagementExtension.log). This line appears ROUTINELY during the device phase (no user token exists yet), so the agent holds the failure pending: any IME-TOKEN-SUCCESS match clears it, and the ime_token_failure Warning fires only when no success follows for the whole 30-min grace window (then deduped to one Warning per distinct errorCode). A genuine auth outage (WAM broken, conditional access, network) runs long enough to hit the window. Verified against IME 1.97 and 1.104 decompiled sources.",
+      "description": "IME token acquisition failure ('Failed to get AAD token. len = N using client id ... and resource id ..., errorCode = N', IntuneTokenManager, IntuneManagementExtension.log). This line appears ROUTINELY during the device phase (no user token exists yet), so the agent holds the failure pending: any IME-TOKEN-SUCCESS match clears it, and the ime_token_failure Warning fires only when no success follows for the whole 30-min grace window (then deduped to one Warning per distinct errorCode). A genuine auth outage (WAM broken, conditional access, network) runs long enough to hit the window. Verified against IME 1.97 and 1.104.",
       "enabled": true
     },
     {

rules/ime-log-patterns/IME-DO-TEL.json

@@ -4,6 +4,6 @@
   "category": "currentPhase",
   "pattern": "^\\[DO TEL\\] = (?<doTelJson>\\{.*\\})",
   "action": "updateDoTelemetry",
-  "description": "Captures Delivery Optimization telemetry JSON after a DO download completes. Contains file size, peer caching stats, download mode, and duration. IME removed the [DO TEL] emitter in 1.104 (absent in 1.104.102.0 and 1.105.103.0 decompiles, present in 1.97.107.0); kept while 1.101/1.103 devices are in the fleet — retire once those versions are gone.",
+  "description": "Captures Delivery Optimization telemetry JSON after a DO download completes. Contains file size, peer caching stats, download mode, and duration. IME removed the [DO TEL] emitter in 1.104 (absent from the 1.104.102.0 and 1.105.103.0 builds, present in 1.97.107.0); kept while 1.101/1.103 devices are in the fleet — retire once those versions are gone.",
   "enabled": true
 }

rules/ime-log-patterns/IME-TOKEN-FAILURE.json

@@ -4,6 +4,6 @@
   "category": "always",
   "pattern": "^Failed to get AAD token\\..*?errorCode = (?<errorCode>.*?)$",
   "action": "imeTokenFailure",
-  "description": "IME token acquisition failure ('Failed to get AAD token. len = N using client id ... and resource id ..., errorCode = N', IntuneTokenManager, IntuneManagementExtension.log). This line appears ROUTINELY during the device phase (no user token exists yet), so the agent holds the failure pending: any IME-TOKEN-SUCCESS match clears it, and the ime_token_failure Warning fires only when no success follows for the whole 30-min grace window (then deduped to one Warning per distinct errorCode). A genuine auth outage (WAM broken, conditional access, network) runs long enough to hit the window. Verified against IME 1.97 and 1.104 decompiled sources.",
+  "description": "IME token acquisition failure ('Failed to get AAD token. len = N using client id ... and resource id ..., errorCode = N', IntuneTokenManager, IntuneManagementExtension.log). This line appears ROUTINELY during the device phase (no user token exists yet), so the agent holds the failure pending: any IME-TOKEN-SUCCESS match clears it, and the ime_token_failure Warning fires only when no success follows for the whole 30-min grace window (then deduped to one Warning per distinct errorCode). A genuine auth outage (WAM broken, conditional access, network) runs long enough to hit the window. Verified against IME 1.97 and 1.104.",
   "enabled": true
 }

scripts/CustomerSetup/Grant-AutopilotMonitorAddOn.ps1

@@ -75,15 +75,17 @@
 .NOTES
     Requires:
       - Microsoft.Graph.Authentication PowerShell module (auto-installs if missing).
-      - Sign-in as Global Administrator OR Privileged Role Administrator OR Cloud Application Administrator.
+      - Sign-in as Global Administrator OR Privileged Role Administrator (with PIM, activate the
+        role first). Only these roles may assign Microsoft Graph application permissions;
+        Application Administrator and Cloud Application Administrator are not enough.
+      - The Autopilot Monitor app must be admin-consented in your tenant first
+        (its service principal must exist before grants can be added).
 
     Sign-in behaviour:
       In Azure Cloud Shell the script signs in via the ambient identity endpoint (a delegated
       token for the already-signed-in user) - no device-code prompt, which Conditional Access
       policies commonly block. Outside Cloud Shell it falls back to a normal interactive
       Microsoft Graph sign-in. -TenantId only applies to the interactive fallback.
-      - The Autopilot Monitor app must be admin-consented in your tenant first
-        (its service principal must exist before grants can be added).
 
     After granting:
       The Autopilot Monitor backend may cache an older token for up to ~1 hour. Use the
@@ -139,6 +141,36 @@ if ($PSCmdlet.ParameterSetName -eq 'ByFeatures') {
 # ---- Constants ----
 $MicrosoftGraphAppId = '00000003-0000-0000-c000-000000000000'
 
+# ---- Graph failure details ----
+# Invoke-MgGraphRequest puts only "Response status code does not indicate success: ..." into the
+# exception message. Graph's own error (code + message) is the response body in ErrorDetails,
+# behind the request line, the status line and the headers. Some headers carry JSON themselves
+# (x-ms-ags-diagnostic), so the body is taken from behind the blank line that ends the headers.
+function Get-GraphFailure {
+    param([System.Management.Automation.ErrorRecord]$ErrorRecord)
+
+    $status = 0
+    if ($ErrorRecord.Exception.PSObject.Properties['Response'] -and $ErrorRecord.Exception.Response) {
+        $status = [int]$ErrorRecord.Exception.Response.StatusCode
+    }
+
+    $text = $ErrorRecord.Exception.Message
+    if ($ErrorRecord.ErrorDetails -and $ErrorRecord.ErrorDetails.Message) {
+        $body = ($ErrorRecord.ErrorDetails.Message -split '\r?\n\r?\n', 2)[-1].Trim()
+        if ($body.StartsWith('{')) {
+            try {
+                $graphError = ($body | ConvertFrom-Json).error
+                if ($graphError.code) { $text = "$($graphError.code): $($graphError.message)" }
+            }
+            catch {
+                # Not a Graph JSON body - keep the exception message.
+            }
+        }
+    }
+
+    [pscustomobject]@{ Status = $status; Text = $text }
+}
+
 # ---- Pre-flight: module ----
 if (-not (Get-Module -ListAvailable -Name Microsoft.Graph.Authentication)) {
     Write-Host "[Setup] Microsoft.Graph.Authentication not installed. Installing for current user..." -ForegroundColor Yellow
@@ -188,7 +220,7 @@ Write-Host "[Auth] Granted scopes: $($ctx.Scopes -join ', ')"
 # carries a fixed scope set (incl. Directory.AccessAsUser.All) instead of the requested scopes,
 # and its effective rights follow the signed-in user's directory role.
 if (-not $identityConnected -and -not ($ctx.Scopes -contains 'AppRoleAssignment.ReadWrite.All')) {
-    Write-Warning "Scope 'AppRoleAssignment.ReadWrite.All' was NOT granted. The signed-in user likely lacks the required role (Global Admin / Privileged Role Admin / Cloud App Admin)."
+    Write-Warning "Scope 'AppRoleAssignment.ReadWrite.All' was NOT granted. The signed-in user likely lacks the required role (Global Administrator or Privileged Role Administrator)."
     if (-not $VerifyOnly) { return }
 }
 
@@ -262,6 +294,7 @@ $action = if ($Revoke) { 'Revoke' } else { 'Grant' }
 Write-Host "[4/4] $action mode - processing $($Permissions.Count) permission(s)..." -ForegroundColor Cyan
 
 $results = @()
+$graphForbidden = $false
 foreach ($permName in $Permissions) {
     $appRole = $graphSp.appRoles | Where-Object {
         $_.value -eq $permName -and $_.allowedMemberTypes -contains 'Application'
@@ -288,7 +321,9 @@ foreach ($permName in $Permissions) {
                 $results += [pscustomobject]@{ Permission = $permName; Status = 'Revoked' }
             }
             catch {
-                Write-Warning "  [FAIL]  '$permName' revoke failed: $($_.Exception.Message)"
+                $failure = Get-GraphFailure $_
+                if ($failure.Status -eq 403) { $graphForbidden = $true }
+                Write-Warning "  [FAIL]  '$permName' revoke failed: $($failure.Text)"
                 $results += [pscustomobject]@{ Permission = $permName; Status = 'Failed' }
             }
         }
@@ -315,7 +350,9 @@ foreach ($permName in $Permissions) {
             $results += [pscustomobject]@{ Permission = $permName; Status = 'Granted' }
         }
         catch {
-            Write-Warning "  [FAIL]  '$permName' grant failed: $($_.Exception.Message)"
+            $failure = Get-GraphFailure $_
+            if ($failure.Status -eq 403) { $graphForbidden = $true }
+            Write-Warning "  [FAIL]  '$permName' grant failed: $($failure.Text)"
             $results += [pscustomobject]@{ Permission = $permName; Status = 'Failed' }
         }
     }
@@ -324,6 +361,9 @@ foreach ($permName in $Permissions) {
 Write-Host ""
 Write-Host "=========== Summary ===========" -ForegroundColor Cyan
 $results | Format-Table -AutoSize | Out-Host
+if ($graphForbidden) {
+    Write-Warning "Microsoft Graph refused the change (403): the signed-in account may not manage Microsoft Graph application permissions. Sign in as Global Administrator or Privileged Role Administrator (with PIM, activate the role first) and run the script again."
+}
 Write-Host ""
 Write-Host "Note: token-cached backends may need up to ~1h to see the new permission set." -ForegroundColor Yellow
 Write-Host "      Use 'Refresh permission status' in the admin UI to apply changes immediately." -ForegroundColor Yellow

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/GatherRuleCollectorGuardTests.cs

@@ -41,15 +41,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
         }
 
         private GatherRuleContext Context(bool unrestricted = false, string? imeLogPathOverride = null)
-            => new GatherRuleContext(
-                new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+        {
+            var logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
+            return new GatherRuleContext(
+                logger,
                 "sess", "tenant",
                 evt => _events.Add(evt),
                 imeLogPathOverride,
-                new LogFilePositionTracker())
+                new GatherRuleSessionState("sess", null, logger))
             {
                 UnrestrictedMode = unrestricted
             };
+        }
 
         private static GatherRule Rule(string collectorType, string target,
             Dictionary<string, string>? parameters = null) => new GatherRule

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/GatherRuleDebugLogTests.cs

@@ -94,7 +94,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
         public void Context_DebugLog_is_noop_without_writer()
         {
             var context = new GatherRuleContext(
-                _logger, "sess", "tenant", _ => { }, null, new LogFilePositionTracker());
+                _logger, "sess", "tenant", _ => { }, null, new GatherRuleSessionState("sess", null, _logger));
 
             context.DebugLog("RULE-1", GatherRuleDebugLog.StageScope, "should not throw, should not write");
 

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/GatherRuleExecutorRestartTests.cs

@@ -0,0 +1,220 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
+{
+    /// <summary>
+    /// An agent restart inside one enrollment session — a new <see cref="GatherRuleExecutor"/> on the
+    /// same state directory — continues where the previous run stopped: logparser rules do not
+    /// replay their log, on_change rules do not re-emit an unchanged result. Regression anchor:
+    /// session c8106021, where every restart replayed the whole HP Image Assistant log (70 events).
+    /// </summary>
+    [Collection("SerialThreading")] // startup rules execute on the shared ThreadPool
+    public sealed class GatherRuleExecutorRestartTests : IDisposable
+    {
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly TempDirectory _stateDir = new TempDirectory();
+        private readonly List<EnrollmentEvent> _events = new List<EnrollmentEvent>();
+        private readonly object _eventsGate = new object();
+        private readonly List<GatherRuleExecutor> _executors = new List<GatherRuleExecutor>();
+
+        // %TEMP% lives under C:\Users (hard-blocked) — log targets sit beside the test assembly.
+        private readonly string _logDir = Path.Combine(
+            AppContext.BaseDirectory, "gather-restart-tests-" + Guid.NewGuid().ToString("N"));
+
+        public GatherRuleExecutorRestartTests()
+        {
+            Directory.CreateDirectory(_logDir);
+        }
+
+        public void Dispose()
+        {
+            foreach (var executor in _executors)
+                executor.Dispose();
+            _tmp.Dispose();
+            _stateDir.Dispose();
+            try { Directory.Delete(_logDir, recursive: true); } catch { /* best effort */ }
+        }
+
+        private string StateFile => Path.Combine(_stateDir.Path, GatherRuleStatePersistence.FileName);
+
+        private List<EnrollmentEvent> Events
+        {
+            get { lock (_eventsGate) return _events.ToList(); }
+        }
+
+        /// <summary>One agent run: a fresh executor whose startup rules run once. Not disposed — a hard kill.</summary>
+        private GatherRuleExecutor AgentRun(GatherRule rule, string sessionId = "session-a", string? stateDirectory = "default",
+            Action<EnrollmentEvent>? onEvent = null, string? debugLogPath = null)
+        {
+            var executor = new GatherRuleExecutor(
+                sessionId, "tenant",
+                evt =>
+                {
+                    onEvent?.Invoke(evt);
+                    lock (_eventsGate) _events.Add(evt);
+                },
+                new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                debugLogPath: debugLogPath,
+                stateDirectory: stateDirectory == "default" ? _stateDir.Path : stateDirectory)
+            {
+                UnrestrictedMode = true
+            };
+            _executors.Add(executor);
+            executor.UpdateRules(new List<GatherRule> { rule });
+            Assert.True(executor.WaitForStartupRules(30));
+            return executor;
+        }
+
+        private static GatherRule LogRule(string path, string id = "hpia-log-collect") => new GatherRule
+        {
+            RuleId = id,
+            Title = id,
+            CollectorType = "logparser",
+            Target = path,
+            Parameters = new Dictionary<string, string> { ["pattern"] = "^(?<status>Update .+)$", ["format"] = "text" },
+            Trigger = "startup",
+            OutputEventType = "HPiA-UpdateStatus",
+            Enabled = true,
+        };
+
+        private static GatherRule OnChangeFileRule(string path) => new GatherRule
+        {
+            RuleId = "GATHER-OC-FILE",
+            Title = "file presence",
+            CollectorType = "file",
+            Target = path,
+            Trigger = "startup",
+            OutputEventType = "gather_file_presence",
+            Enabled = true,
+            EmitMode = "on_change",
+        };
+
+        private string WriteLog(string name, string content)
+        {
+            var path = Path.Combine(_logDir, name);
+            File.WriteAllText(path, content);
+            return path;
+        }
+
+        private int StatusEvents => Events.Count(e => e.EventType == "HPiA-UpdateStatus");
+
+        [Fact]
+        public void Restart_does_not_replay_the_log_and_new_lines_arrive_once()
+        {
+            var path = WriteLog("HP Image Assistant.log", "Update one\nUpdate two\nnoise\n");
+
+            AgentRun(LogRule(path));
+            Assert.Equal(2, StatusEvents);
+
+            AgentRun(LogRule(path));                      // reboot, nothing new
+            Assert.Equal(2, StatusEvents);
+
+            File.AppendAllText(path, "Update three\n");
+            AgentRun(LogRule(path));                      // next restart picks up only the new line
+            Assert.Equal(3, StatusEvents);
+            Assert.Equal("Update three", Events.Last(e => e.EventType == "HPiA-UpdateStatus").Data["status"]);
+        }
+
+        [Fact]
+        public void Position_is_on_disk_right_after_the_run_without_a_clean_shutdown()
+        {
+            var path = WriteLog("hardkill.log", "Update one\n");
+
+            AgentRun(LogRule(path));                      // never disposed
+
+            var saved = JsonConvert.DeserializeObject<GatherRuleStateData>(File.ReadAllText(StateFile))!;
+            var position = Assert.Single(saved.LogPositions!);
+            Assert.Equal(new FileInfo(path).Length, position.Position);
+            Assert.Equal("session-a", saved.SessionId);
+        }
+
+        [Fact]
+        public void Position_is_saved_only_after_the_events_went_out()
+        {
+            var path = WriteLog("ordering.log", "Update one\n");
+            var savedDuringEmit = new List<bool>();
+
+            AgentRun(LogRule(path), onEvent: _ => savedDuringEmit.Add(File.Exists(StateFile)));
+
+            Assert.Equal(new[] { false }, savedDuringEmit);
+            Assert.True(File.Exists(StateFile));
+        }
+
+        [Fact]
+        public void A_new_session_reads_the_log_from_the_beginning()
+        {
+            var path = WriteLog("rotated.log", "Update one\nUpdate two\n");
+            AgentRun(LogRule(path), sessionId: "session-a");
+
+            AgentRun(LogRule(path), sessionId: "session-b");   // session rotated on the same device
+
+            Assert.Equal(4, StatusEvents);
+        }
+
+        [Fact]
+        public void A_log_replaced_during_the_reboot_is_read_from_the_beginning()
+        {
+            var path = WriteLog("replaced.log", "Update one\n");
+            AgentRun(LogRule(path, "replaced"));
+
+            // The tool writes a new log after the reboot; it is already longer than the old position.
+            File.WriteAllText(path, "Update fresh A\nUpdate fresh B\nUpdate fresh C\n");
+            AgentRun(LogRule(path, "replaced"));
+
+            Assert.Equal(new[] { "Update one", "Update fresh A", "Update fresh B", "Update fresh C" },
+                Events.Where(e => e.EventType == "HPiA-UpdateStatus").Select(e => (string)e.Data["status"]).ToArray());
+        }
+
+        [Fact]
+        public void An_unchanged_on_change_result_stays_silent_after_a_restart()
+        {
+            var watched = Path.Combine(_logDir, "marker.txt");
+
+            AgentRun(OnChangeFileRule(watched));          // absent → first result emits
+            AgentRun(OnChangeFileRule(watched));          // reboot, still absent → silent
+            Assert.Single(Events, e => e.EventType == "gather_file_presence");
+
+            File.WriteAllText(watched, "present");
+            AgentRun(OnChangeFileRule(watched));          // changed → emits
+
+            Assert.Equal(2, Events.Count(e => e.EventType == "gather_file_presence"));
+        }
+
+        [Fact]
+        public void Without_a_state_directory_every_run_starts_over_and_writes_nothing()
+        {
+            var path = WriteLog("diagnostic.log", "Update one\n");
+
+            AgentRun(LogRule(path), stateDirectory: null);
+            AgentRun(LogRule(path), stateDirectory: null);
+
+            Assert.Equal(2, StatusEvents);
+            Assert.False(File.Exists(StateFile));
+        }
+
+        [Fact]
+        public void Debug_trace_says_what_was_restored_and_where_reading_continues()
+        {
+            var path = WriteLog("traced.log", "Update one\n");
+            var trace = Path.Combine(_tmp.Path, "gather-rules-debug.log");
+            AgentRun(LogRule(path));
+            File.AppendAllText(path, "Update two\n");
+
+            AgentRun(LogRule(path), debugLogPath: trace);
+
+            var text = File.ReadAllText(trace);
+            Assert.Contains("gather state: restored 1 logparser position(s) for 1 rule(s)", text);
+            Assert.Contains("hpia-log-collect | config | logparser position restored: traced.log", text);
+            Assert.Contains("traced.log: continuing at position", text);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/GatherRuleSessionStateTests.cs

@@ -0,0 +1,278 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
+{
+    /// <summary>
+    /// <see cref="GatherRuleSessionState"/> and <see cref="GatherRuleStatePersistence"/>: what is
+    /// written, what a restart restores, what it refuses, and when the file is (not) written.
+    /// </summary>
+    public sealed class GatherRuleSessionStateTests : IDisposable
+    {
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly TempDirectory _stateDir = new TempDirectory();
+        private readonly AgentLogger _logger;
+
+        public GatherRuleSessionStateTests()
+        {
+            _logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
+        }
+
+        public void Dispose()
+        {
+            _tmp.Dispose();
+            _stateDir.Dispose();
+        }
+
+        private string StateFile => Path.Combine(_stateDir.Path, GatherRuleStatePersistence.FileName);
+
+        private GatherRuleSessionState NewState(string sessionId = "session-a") =>
+            new GatherRuleSessionState(sessionId, new GatherRuleStatePersistence(_stateDir.Path, _logger), _logger);
+
+        private static LogFileHead Head(string text) => LogFileHead.FromBytes(Encoding.UTF8.GetBytes(text));
+
+        // ── restore ─────────────────────────────────────────────────────────
+
+        [Fact]
+        public void Positions_and_emitted_hashes_survive_a_restart_of_the_same_session()
+        {
+            var first = NewState();
+            first.CommitLogPosition("RULE-1", @"C:\Logs\a.log", 120, 7, Head("2026-09-28 a.log start"), heldTailStart: -1);
+            first.CommitEmittedHash("RULE-2", "hash-value");
+
+            var second = NewState();
+
+            var position = second.PeekLogPosition("RULE-1", @"C:\Logs\a.log");
+            Assert.NotNull(position);
+            Assert.Equal(120, position!.Position);
+            Assert.Equal(7, position.LineNumber);
+            Assert.True(position.FromPreviousRun);
+            Assert.Equal("hash-value", second.GetEmittedHashes()["RULE-2"]);
+            Assert.StartsWith("restored 1 logparser position(s) for 1 rule(s) and 1 on_change value(s)", second.RestoreSummary);
+        }
+
+        [Fact]
+        public void State_of_another_session_is_ignored()
+        {
+            NewState("session-a").CommitLogPosition("RULE-1", @"C:\Logs\a.log", 120, 7, Head("start"), -1);
+
+            var rotated = NewState("session-b");
+
+            Assert.Null(rotated.PeekLogPosition("RULE-1", @"C:\Logs\a.log"));
+            Assert.Contains("saved for session session-a, current session is session-b", rotated.RestoreSummary);
+        }
+
+        [Fact]
+        public void Missing_file_is_a_first_run_and_corrupt_file_a_fresh_start()
+        {
+            Assert.StartsWith("no saved state", NewState().RestoreSummary);
+
+            File.WriteAllText(StateFile, "not json {{{");
+            var afterCorruption = NewState();
+
+            Assert.StartsWith("saved state discarded", afterCorruption.RestoreSummary);
+            Assert.Empty(afterCorruption.GetEmittedHashes());
+        }
+
+        [Fact]
+        public void Tampered_entries_are_dropped_and_the_rest_restored()
+        {
+            var data = new GatherRuleStateData
+            {
+                SessionId = "session-a",
+                SavedAtUtc = DateTime.UtcNow,
+                LogPositions = new List<GatherLogPositionData>
+                {
+                    new GatherLogPositionData { RuleId = "OK", Path = @"C:\a.log", Position = 10, LineNumber = 1, HeadLength = 10, HeadHash = "h" },
+                    new GatherLogPositionData { RuleId = "NEG", Path = @"C:\b.log", Position = -5, HeadLength = 10, HeadHash = "h" },
+                    new GatherLogPositionData { RuleId = "", Path = @"C:\c.log", Position = 1, HeadLength = 1, HeadHash = "h" },
+                    new GatherLogPositionData { RuleId = "BIGHEAD", Path = @"C:\d.log", Position = 1, HeadLength = 5000, HeadHash = "h" },
+                    new GatherLogPositionData { RuleId = "NOHEAD", Path = @"C:\e.log", Position = 50, HeadLength = 0 },
+                },
+                OnChangeHashes = new Dictionary<string, string> { ["GOOD"] = "x", ["EMPTY"] = "" },
+            };
+            File.WriteAllText(StateFile, JsonConvert.SerializeObject(data));
+
+            var state = NewState();
+
+            Assert.NotNull(state.PeekLogPosition("OK", @"C:\a.log"));
+            Assert.Null(state.PeekLogPosition("NEG", @"C:\b.log"));
+            Assert.Null(state.PeekLogPosition("BIGHEAD", @"C:\d.log"));
+            Assert.Null(state.PeekLogPosition("NOHEAD", @"C:\e.log"));
+            Assert.Equal(new[] { "GOOD" }, state.GetEmittedHashes().Keys.ToArray());
+            Assert.Contains("5 invalid entries dropped", state.RestoreSummary);
+        }
+
+        [Fact]
+        public void A_path_no_real_file_can_have_is_dropped_and_never_stops_the_executor()
+        {
+            // Path APIs throw on these characters under .NET Framework; a throw here would keep
+            // every collector host down at every restart of the session.
+            var data = new GatherRuleStateData
+            {
+                SessionId = "session-a",
+                LogPositions = new List<GatherLogPositionData>
+                {
+                    new GatherLogPositionData { RuleId = "BAD", Path = "C:\\Logs\\x.|og", Position = 1, HeadLength = 1, HeadHash = "h" },
+                    new GatherLogPositionData { RuleId = "WILD", Path = "C:\\Logs\\*.log", Position = 1, HeadLength = 1, HeadHash = "h" },
+                    new GatherLogPositionData { RuleId = "OK", Path = "C:\\Logs\\ok.log", Position = 1, HeadLength = 1, HeadHash = "h" },
+                },
+            };
+            File.WriteAllText(StateFile, JsonConvert.SerializeObject(data));
+
+            var state = NewState();
+
+            Assert.NotNull(state.PeekLogPosition("OK", "C:\\Logs\\ok.log"));
+            Assert.Null(state.PeekLogPosition("BAD", "C:\\Logs\\x.|og"));
+            Assert.Contains("2 invalid entries dropped", state.RestoreSummary);
+        }
+
+        // ── where reading starts ────────────────────────────────────────────
+
+        [Fact]
+        public void Reading_continues_while_the_file_head_still_matches()
+        {
+            var state = NewState();
+            state.CommitLogPosition("R", @"C:\a.log", 30, 3, Head("2026-09-28 first line\n"), -1);
+
+            var start = GatherRuleSessionState.ResolveStart(state.PeekLogPosition("R", @"C:\a.log"), 200,
+                Head("2026-09-28 first line\nsecond line\nthird"), out var how);
+
+            Assert.Equal(30, start);
+            Assert.Equal(LogReadStart.Continue, how);
+        }
+
+        [Fact]
+        public void A_shrunk_file_and_a_replaced_file_are_read_from_the_beginning()
+        {
+            var state = NewState();
+            state.CommitLogPosition("R", @"C:\a.log", 30, 3, Head("2026-09-28 first line\n"), -1);
+            var known = state.PeekLogPosition("R", @"C:\a.log");
+
+            Assert.Equal(0, GatherRuleSessionState.ResolveStart(known, 20, Head("2026-09-28 fir"), out var shrunk));
+            Assert.Equal(LogReadStart.Shrunk, shrunk);
+
+            // Replaced and already longer than the old position: only the head tells.
+            Assert.Equal(0, GatherRuleSessionState.ResolveStart(known, 500, Head("2026-09-30 a new log entirely, much longer"), out var replaced));
+            Assert.Equal(LogReadStart.Replaced, replaced);
+
+            // Shorter than the recorded head although not shorter than the position.
+            state.CommitLogPosition("S", @"C:\b.log", 5, 1, Head("0123456789abcdef"), -1);
+            Assert.Equal(0, GatherRuleSessionState.ResolveStart(state.PeekLogPosition("S", @"C:\b.log"), 8, Head("01234567"), out var cut));
+            Assert.Equal(LogReadStart.Replaced, cut);
+        }
+
+        [Fact]
+        public void Positions_are_kept_per_rule_for_the_same_file()
+        {
+            var state = NewState();
+            state.CommitLogPosition("RULE-A", @"C:\shared.log", 100, 10, Head("x"), -1);
+
+            Assert.Null(state.PeekLogPosition("RULE-B", @"C:\shared.log"));
+            Assert.NotNull(state.PeekLogPosition("RULE-A", @"C:\SHARED.LOG")); // paths compare case-insensitively
+        }
+
+        // ── when the file is written ────────────────────────────────────────
+
+        [Fact]
+        public void An_unchanged_commit_does_not_write_the_file()
+        {
+            var state = NewState();
+            state.CommitLogPosition("R", @"C:\a.log", 10, 1, Head("head"), -1);
+            File.Delete(StateFile);
+
+            state.CommitLogPosition("R", @"C:\a.log", 10, 1, Head("head"), -1);
+            state.CommitEmittedHash("H", "v");
+            File.Delete(StateFile);
+            state.CommitEmittedHash("H", "v");
+
+            Assert.False(File.Exists(StateFile));
+        }
+
+        [Fact]
+        public void A_failed_save_is_retried_at_the_next_commit()
+        {
+            var blocked = Path.Combine(_stateDir.Path, "blocked");
+            File.WriteAllText(blocked, "a file where the state directory should be");
+            var state = new GatherRuleSessionState("session-a", new GatherRuleStatePersistence(blocked, _logger), _logger);
+
+            state.CommitEmittedHash("H", "v");   // Directory.CreateDirectory fails
+            File.Delete(blocked);
+            state.CommitEmittedHash("H", "v");   // unchanged, but the earlier save is still owed
+
+            Assert.True(File.Exists(Path.Combine(blocked, GatherRuleStatePersistence.FileName)));
+        }
+
+        [Fact]
+        public void A_closed_state_no_longer_writes()
+        {
+            var state = NewState();
+            state.Close();
+
+            state.CommitEmittedHash("H", "v");
+
+            Assert.False(File.Exists(StateFile));
+        }
+
+        [Fact]
+        public void Without_persistence_nothing_is_written()
+        {
+            var state = new GatherRuleSessionState("session-a", null, _logger);
+
+            state.CommitLogPosition("R", @"C:\a.log", 10, 1, Head("head"), -1);
+
+            Assert.StartsWith("persistence off", state.RestoreSummary);
+            Assert.Empty(Directory.GetFiles(_stateDir.Path));
+        }
+
+        // ── bounds and concurrency ──────────────────────────────────────────
+
+        [Fact]
+        public void A_rule_forgets_its_least_recently_touched_file_beyond_the_cap()
+        {
+            var state = NewState();
+            for (var i = 0; i < GatherRuleSessionState.MaxLogFilesPerRule; i++)
+                state.CommitLogPosition("R", $@"C:\logs\{i}.log", 1, 1, Head("h"), -1);
+            state.PeekLogPosition("R", @"C:\logs\0.log");   // touched again — survives
+
+            state.CommitLogPosition("R", @"C:\logs\new.log", 1, 1, Head("h"), -1);
+
+            Assert.NotNull(state.PeekLogPosition("R", @"C:\logs\0.log"));
+            Assert.Null(state.PeekLogPosition("R", @"C:\logs\1.log"));
+            Assert.NotNull(state.PeekLogPosition("R", @"C:\logs\new.log"));
+        }
+
+        [Fact]
+        public void Parallel_commits_leave_a_consistent_file()
+        {
+            var state = NewState();
+
+            Parallel.For(0, 8, worker =>
+            {
+                for (var i = 0; i < 50; i++)
+                {
+                    state.CommitLogPosition($"RULE-{worker}", $@"C:\logs\{worker}.log", i + 1, i, Head("h"), -1);
+                    state.PeekLogPosition($"RULE-{worker}", $@"C:\logs\{worker}.log");
+                    state.CommitEmittedHash($"RULE-{worker}", "hash-" + i);
+                }
+            });
+
+            var restored = NewState();
+            for (var worker = 0; worker < 8; worker++)
+            {
+                Assert.Equal(50, restored.PeekLogPosition($"RULE-{worker}", $@"C:\logs\{worker}.log")!.Position);
+                Assert.Equal("hash-49", restored.GetEmittedHashes()[$"RULE-{worker}"]);
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/LogLineReaderTests.cs

@@ -0,0 +1,188 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
+{
+    /// <summary>
+    /// <see cref="LogLineReader"/>, <see cref="LogTextEncoding"/> and <see cref="LogFileHead"/>:
+    /// exact byte positions, StreamReader-compatible line ends, byte order marks only at offset 0,
+    /// and the code-unit view of UTF-16/UTF-32 files.
+    /// </summary>
+    public sealed class LogLineReaderTests
+    {
+        private static byte[] Bytes(Encoding encoding, string text, bool withBom = true)
+        {
+            var body = encoding.GetBytes(text);
+            return withBom ? encoding.GetPreamble().Concat(body).ToArray() : body;
+        }
+
+        private static (List<string> Lines, List<long> EndPositions, List<bool> Terminated) ReadAll(
+            byte[] file, long start = 0, int maxLineBytes = 1024)
+        {
+            var encoding = LogFileHead.FromBytes(file.Take(LogFileHead.MaxBytes).ToArray()).Encoding;
+            using (var stream = new MemoryStream(file))
+            {
+                stream.Seek(start, SeekOrigin.Begin);
+                var reader = new LogLineReader(stream, encoding, maxLineBytes);
+                var lines = new List<string>();
+                var ends = new List<long>();
+                var terminated = new List<bool>();
+                string line;
+                while ((line = reader.ReadLine()) != null)
+                {
+                    lines.Add(line);
+                    ends.Add(reader.Position);
+                    terminated.Add(reader.LastLineTerminated);
+                }
+                return (lines, ends, terminated);
+            }
+        }
+
+        [Fact]
+        public void Line_ends_match_StreamReader_including_a_lone_carriage_return()
+        {
+            var file = Encoding.UTF8.GetBytes("one\ntwo\r\nthree\rfour");
+
+            var result = ReadAll(file);
+
+            Assert.Equal(new[] { "one", "two", "three", "four" }, result.Lines);
+            Assert.Equal(new long[] { 4, 9, 15, 19 }, result.EndPositions);
+            Assert.Equal(new[] { true, true, true, false }, result.Terminated);
+        }
+
+        [Fact]
+        public void Position_after_each_line_is_the_offset_to_resume_from()
+        {
+            var file = Encoding.UTF8.GetBytes("alpha\nbeta\ngamma\n");
+
+            var first = ReadAll(file);
+            var resumed = ReadAll(file, start: first.EndPositions[0]);
+
+            Assert.Equal(new[] { "beta", "gamma" }, resumed.Lines);
+            Assert.Equal(file.Length, resumed.EndPositions.Last());
+        }
+
+        [Fact]
+        public void Utf8_byte_order_mark_is_skipped_only_at_offset_0()
+        {
+            var file = Bytes(Encoding.UTF8, "first\nsecond\n");
+
+            var result = ReadAll(file);
+
+            Assert.Equal(new[] { "first", "second" }, result.Lines);
+            Assert.Equal(LogTextEncoding.Utf8WithBom, LogFileHead.FromBytes(file).Encoding);
+        }
+
+        [Theory]
+        [InlineData("utf-16le")]
+        [InlineData("utf-16be")]
+        [InlineData("utf-32le")]
+        [InlineData("utf-32be")]
+        public void Unicode_files_are_read_in_their_code_units_from_any_resume_point(string name)
+        {
+            var encoding = name == "utf-16le" ? Encoding.Unicode
+                : name == "utf-16be" ? Encoding.BigEndianUnicode
+                : name == "utf-32le" ? Encoding.UTF32
+                : new UTF32Encoding(bigEndian: true, byteOrderMark: true);
+            var file = Bytes(encoding, "ERROR first\r\nERROR zweite Zeile mit Umlaut äöü\r\n");
+
+            var whole = ReadAll(file);
+            var resumed = ReadAll(file, start: whole.EndPositions[0]);
+
+            Assert.Equal(name, LogFileHead.FromBytes(file).Encoding.Name);
+            Assert.Equal(new[] { "ERROR first", "ERROR zweite Zeile mit Umlaut äöü" }, whole.Lines);
+            Assert.Equal(new[] { "ERROR zweite Zeile mit Umlaut äöü" }, resumed.Lines);
+            Assert.Equal(file.Length, whole.EndPositions.Last());
+        }
+
+        [Fact]
+        public void File_without_byte_order_mark_is_utf8_and_ansi_bytes_decode_as_before()
+        {
+            var file = new byte[] { (byte)'M', (byte)'a', (byte)'n', 0xFC, (byte)'\n' }; // "Man" + Windows-1252 'ü'
+
+            var result = ReadAll(file);
+
+            Assert.Equal(LogTextEncoding.Utf8, LogFileHead.FromBytes(file).Encoding);
+            Assert.Equal(new StreamReader(new MemoryStream(file), Encoding.UTF8).ReadLine(), result.Lines.Single());
+        }
+
+        [Fact]
+        public void Carriage_return_at_end_of_file_ends_the_line_and_its_late_line_feed_is_skipped()
+        {
+            var firstWrite = Encoding.UTF8.GetBytes("done\r");
+            var later = Encoding.UTF8.GetBytes("done\r\nnext\n");
+
+            var first = ReadAll(firstWrite);
+            var resumed = ReadAll(later, start: first.EndPositions.Last());
+
+            Assert.Equal(new[] { "done" }, first.Lines);
+            Assert.True(first.Terminated.Single());
+            Assert.Equal(new[] { "next" }, resumed.Lines);
+        }
+
+        [Fact]
+        public void Overlong_line_is_consumed_without_being_kept_and_reading_continues_behind_it()
+        {
+            var file = Encoding.UTF8.GetBytes(new string('x', 50) + "\nshort\n");
+            using (var stream = new MemoryStream(file))
+            {
+                var reader = new LogLineReader(stream, LogTextEncoding.Utf8, maxLineBytes: 10);
+
+                Assert.Equal(string.Empty, reader.ReadLine());
+                Assert.True(reader.LastLineTruncated);
+                Assert.Equal(51, reader.Position);
+                Assert.Equal("short", reader.ReadLine());
+                Assert.False(reader.LastLineTruncated);
+                Assert.Null(reader.ReadLine());
+            }
+        }
+
+        [Fact]
+        public void Line_spanning_many_read_buffers_is_returned_whole()
+        {
+            var longLine = new string('y', 200_000);
+            var file = Encoding.UTF8.GetBytes(longLine + "\nend\n");
+
+            var result = ReadAll(file, maxLineBytes: 1_000_000);
+
+            Assert.Equal(new[] { longLine, "end" }, result.Lines);
+        }
+
+        [Fact]
+        public void Half_written_utf16_character_at_end_of_file_stays_in_the_unterminated_line()
+        {
+            var full = Bytes(Encoding.Unicode, "ok\r\nhalf");
+            var file = full.Concat(new byte[] { 0x41 }).ToArray(); // first byte of the next UTF-16 unit
+
+            var result = ReadAll(file);
+
+            Assert.Equal("ok", result.Lines[0]);
+            Assert.False(result.Terminated.Last());
+            Assert.Equal(file.Length, result.EndPositions.Last());
+        }
+
+        [Fact]
+        public void AlignDown_snaps_to_code_units_behind_the_byte_order_mark()
+        {
+            Assert.Equal(0, LogTextEncoding.Utf16LittleEndian.AlignDown(1));
+            Assert.Equal(2, LogTextEncoding.Utf16LittleEndian.AlignDown(3));
+            Assert.Equal(6, LogTextEncoding.Utf16LittleEndian.AlignDown(7));
+            Assert.Equal(8, LogTextEncoding.Utf32LittleEndian.AlignDown(11));
+            Assert.Equal(7, LogTextEncoding.Utf8.AlignDown(7));
+        }
+
+        [Fact]
+        public void Head_hash_of_a_prefix_matches_the_hash_of_the_shorter_file()
+        {
+            var shortFile = LogFileHead.FromBytes(Encoding.UTF8.GetBytes("2026-09-28 start"));
+            var grown = LogFileHead.FromBytes(Encoding.UTF8.GetBytes("2026-09-28 start\nmore lines"));
+
+            Assert.Equal(shortFile.Hash(shortFile.Length), grown.Hash(shortFile.Length));
+            Assert.NotEqual(shortFile.Hash(shortFile.Length), grown.Hash(grown.Length));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/LogParserCollectorDebugLogTests.cs

@@ -37,7 +37,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
                 logger, "sess", "tenant",
                 evt => _events.Add(evt),
                 null,
-                new LogFilePositionTracker(),
+                new GatherRuleSessionState("sess", null, logger),
                 new GatherRuleDebugLog(_debugLogPath, logger))
             {
                 UnrestrictedMode = true

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/LogParserCollectorReadingTests.cs

@@ -0,0 +1,225 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
+{
+    /// <summary>
+    /// Reading semantics of <see cref="LogParserCollector"/> across runs on one context: every
+    /// line of a growing log is matched exactly once — no line lost at a maxLines cut, no line
+    /// split by a writer that is mid-line, UTF-16 logs readable after the first run, positions
+    /// kept per rule, line numbers counted from the start of the file.
+    /// </summary>
+    public sealed class LogParserCollectorReadingTests : IDisposable
+    {
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly List<EnrollmentEvent> _events = new List<EnrollmentEvent>();
+        private readonly GatherRuleContext _context;
+
+        // %TEMP% lives under C:\Users (hard-blocked) — parse targets sit beside the
+        // test assembly instead, admitted via UnrestrictedMode.
+        private readonly string _logDir = Path.Combine(
+            AppContext.BaseDirectory, "gather-reading-tests-" + Guid.NewGuid().ToString("N"));
+
+        public LogParserCollectorReadingTests()
+        {
+            Directory.CreateDirectory(_logDir);
+            _context = NewContext();
+        }
+
+        public void Dispose()
+        {
+            _tmp.Dispose();
+            try { Directory.Delete(_logDir, recursive: true); } catch { /* best effort */ }
+        }
+
+        private GatherRuleContext NewContext()
+        {
+            var logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
+            return new GatherRuleContext(logger, "sess", "tenant",
+                evt => _events.Add(evt), null, new GatherRuleSessionState("sess", null, logger))
+            {
+                UnrestrictedMode = true
+            };
+        }
+
+        private string LogPath(string name) => Path.Combine(_logDir, name);
+
+        private static GatherRule TextRule(string ruleId, string target, string pattern,
+            string trigger = "interval", int? maxLines = null)
+        {
+            var parameters = new Dictionary<string, string> { ["pattern"] = pattern, ["format"] = "text" };
+            if (maxLines.HasValue) parameters["maxLines"] = maxLines.Value.ToString();
+            return new GatherRule
+            {
+                RuleId = ruleId,
+                Title = ruleId,
+                CollectorType = "logparser",
+                Target = target,
+                Parameters = parameters,
+                Trigger = trigger,
+                IntervalSeconds = trigger == "interval" ? 30 : (int?)null,
+                OutputEventType = "logparser_reading_test",
+            };
+        }
+
+        private List<string> Captured(string group) =>
+            _events.Select(e => e.Data.TryGetValue(group, out var v) ? (string)v : "<missing>").ToList();
+
+        [Fact]
+        public void Two_rules_on_one_file_each_read_the_whole_file()
+        {
+            var path = LogPath("shared.log");
+            File.WriteAllText(path, "ERROR one\nWARN two\nERROR three\n");
+            var collector = new LogParserCollector();
+
+            collector.Execute(TextRule("RULE-ERRORS", path, "^ERROR (?<what>\\w+)"), _context);
+            collector.Execute(TextRule("RULE-WARNINGS", path, "^WARN (?<what>\\w+)"), _context);
+
+            Assert.Equal(2, _events.Count(e => (string)e.Data["ruleId"] == "RULE-ERRORS"));
+            Assert.Single(_events, e => (string)e.Data["ruleId"] == "RULE-WARNINGS");
+        }
+
+        [Fact]
+        public void MaxLines_cut_loses_no_line_across_runs()
+        {
+            var path = LogPath("long.log");
+            var sb = new StringBuilder();
+            for (var i = 1; i <= 30; i++)
+                sb.Append("hit ").Append(i.ToString("D3")).Append(' ').Append('x', 90).Append('\n');
+            File.WriteAllText(path, sb.ToString());
+            var rule = TextRule("RULE-LONG", path, "^hit (?<n>\\d{3})", maxLines: 10);
+            var collector = new LogParserCollector();
+
+            for (var run = 0; run < 6; run++)
+                collector.Execute(rule, _context);
+
+            var expected = Enumerable.Range(1, 30).Select(i => i.ToString("D3")).ToList();
+            Assert.Equal(expected, Captured("n"));
+        }
+
+        [Fact]
+        public void Line_written_in_two_parts_is_matched_once_and_whole()
+        {
+            var path = LogPath("partial.log");
+            File.WriteAllText(path, "ERR");
+            var rule = TextRule("RULE-PARTIAL", path, "^ERROR (?<code>0x[0-9A-F]+)$");
+            var collector = new LogParserCollector();
+
+            collector.Execute(rule, _context);          // the writer is mid-line
+            File.AppendAllText(path, "OR 0x1F\n");
+            collector.Execute(rule, _context);
+
+            Assert.Equal(new List<string> { "0x1F" }, Captured("code"));
+        }
+
+        [Fact]
+        public void Interval_rule_reads_a_line_still_unfinished_on_its_second_run_once()
+        {
+            var path = LogPath("never-terminated.log");
+            File.WriteAllText(path, "ERROR 0x2A");
+            var rule = TextRule("RULE-UNFINISHED", path, "^ERROR (?<code>0x[0-9A-F]+)$");
+            var collector = new LogParserCollector();
+
+            collector.Execute(rule, _context);   // held: the writer may still be in the line
+            collector.Execute(rule, _context);   // still unfinished — taken as it is
+            collector.Execute(rule, _context);   // nothing new
+
+            Assert.Equal(new List<string> { "0x2A" }, Captured("code"));
+        }
+
+        [Fact]
+        public void One_shot_rule_reads_an_unfinished_line_now_and_whole_on_its_next_run()
+        {
+            var path = LogPath("startup.log");
+            File.WriteAllText(path, "ok\nERR");
+            var rule = TextRule("RULE-STARTUP", path, "^ERR(?<rest>.*)$", trigger: "startup");
+            var collector = new LogParserCollector();
+
+            collector.Execute(rule, _context);   // agent start: the writer is mid-line
+            File.AppendAllText(path, "OR 0x1F\n");
+            collector.Execute(rule, _context);   // next agent start
+
+            // Read twice, never split: the second read sees the whole line.
+            Assert.Equal(new List<string> { "", "OR 0x1F" }, Captured("rest"));
+            Assert.Equal(new long[] { 2, 2 }, _events.Select(e => Convert.ToInt64(e.Data["logLineNumber"])).ToArray());
+        }
+
+        [Fact]
+        public void Line_feed_written_after_a_trailing_carriage_return_is_consumed_without_a_line()
+        {
+            var path = LogPath("cr-at-end.log");
+            File.WriteAllText(path, "hit\r");
+            var rule = TextRule("RULE-CR", path, "^hit$");
+            var collector = new LogParserCollector();
+
+            collector.Execute(rule, _context);
+            File.AppendAllText(path, "\n");
+            collector.Execute(rule, _context);
+
+            Assert.Single(_events);
+            var position = _context.SessionState.PeekLogPosition("RULE-CR", path);
+            Assert.Equal(new FileInfo(path).Length, position!.Position);
+            Assert.Equal(1, position.LineNumber);
+        }
+
+        [Fact]
+        public void Utf16_log_appended_after_the_first_run_is_still_matched()
+        {
+            var path = LogPath("transcript.log");
+            File.WriteAllText(path, "ERROR first\r\n", Encoding.Unicode);   // UTF-16 LE with BOM
+            var rule = TextRule("RULE-UTF16", path, "^ERROR (?<what>\\w+)$");
+            var collector = new LogParserCollector();
+
+            collector.Execute(rule, _context);
+            using (var stream = new FileStream(path, FileMode.Append, FileAccess.Write))
+            {
+                var bytes = new UnicodeEncoding(bigEndian: false, byteOrderMark: false).GetBytes("ERROR second\r\n");
+                stream.Write(bytes, 0, bytes.Length);
+            }
+            collector.Execute(rule, _context);
+
+            Assert.Equal(new List<string> { "first", "second" }, Captured("what"));
+        }
+
+        [Theory]
+        [InlineData("abc")]
+        [InlineData("0")]
+        [InlineData("-5")]
+        public void MaxLines_that_is_no_positive_number_falls_back_to_the_default(string maxLines)
+        {
+            var path = LogPath("misconfigured.log");
+            File.WriteAllText(path, "hit 1\nhit 2\n");
+            var rule = TextRule("RULE-MISCONFIGURED", path, "^hit (?<n>\\d)$");
+            rule.Parameters["maxLines"] = maxLines;
+
+            new LogParserCollector().Execute(rule, _context);
+
+            Assert.Equal(new List<string> { "1", "2" }, Captured("n"));
+        }
+
+        [Fact]
+        public void Line_numbers_count_from_the_start_of_the_file()
+        {
+            var path = LogPath("numbers.log");
+            File.WriteAllText(path, "a\nhit\nb\n");
+            var rule = TextRule("RULE-NUMBERS", path, "^hit$");
+            var collector = new LogParserCollector();
+
+            collector.Execute(rule, _context);
+            File.AppendAllText(path, "c\nhit\n");
+            collector.Execute(rule, _context);
+
+            Assert.Equal(new long[] { 2, 5 }, _events.Select(e => Convert.ToInt64(e.Data["logLineNumber"])).ToArray());
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/RegistryCollectorEmitOnlyIfExistsTests.cs

@@ -35,7 +35,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
                 tenantId: "tenant",
                 onEventCollected: _ => { },
                 imeLogPathOverride: null,
-                filePositionTracker: new LogFilePositionTracker())
+                sessionState: new GatherRuleSessionState("sess", null, logger))
             {
                 // Bypass the registry allowlist guard for the synthetic test path.
                 UnrestrictedMode = true

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/HelloTrackerCompletionBudgetTests.cs

@@ -0,0 +1,71 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.Shared;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring
+{
+    /// <summary>
+    /// The completion timer a started Hello wizard runs against is the tenant's Hello wait
+    /// (<c>HelloWaitTimeoutSeconds</c>), resolved to 300..3600 s — the same budget the engine's
+    /// hello_safety window spends from the ESP exit, so a tenant allowing an hour is not cut off
+    /// by a fixed 5-min tracker timer while the user is still inside the wizard.
+    /// </summary>
+    public sealed class HelloTrackerCompletionBudgetTests
+    {
+        private static readonly DateTime Fixed = new DateTime(2026, 9, 29, 8, 0, 0, DateTimeKind.Utc);
+
+        [Theory]
+        [InlineData(30, 300)]     // the old default, still stored for many tenants → the built-in window
+        [InlineData(0, 300)]
+        [InlineData(300, 300)]
+        [InlineData(1800, 1800)]
+        [InlineData(3600, 3600)]
+        [InlineData(86400, 3600)] // clamped to the ceiling
+        public void Completion_budget_is_the_resolved_tenant_hello_wait(int configured, int expected)
+        {
+            using var tmp = new TempDirectory();
+            using var tracker = NewTracker(tmp, new FakeSignalIngressSink(), configured);
+
+            Assert.Equal(expected, tracker.CompletionTimeoutSecondsForTest);
+        }
+
+        [Fact]
+        public void Completion_timeout_event_reports_the_tenant_budget()
+        {
+            using var tmp = new TempDirectory();
+            var ingress = new FakeSignalIngressSink();
+            using var tracker = NewTracker(tmp, ingress, helloWaitTimeoutSeconds: 2400);
+
+            tracker.NotifyHelloWizardStarted();
+            Assert.True(tracker.IsCompletionTimerActiveForTest);
+            tracker.TriggerCompletionTimeoutForTest();
+
+            var timeout = ingress.Posted.Single(p =>
+                p.Kind == DecisionSignalKind.InformationalEvent
+                && p.Payload != null
+                && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                && et == Constants.EventTypes.HelloCompletionTimeout);
+            var data = Assert.IsAssignableFrom<IDictionary<string, object>>(timeout.TypedPayload);
+            Assert.Equal(2400, data["timeoutSeconds"]);
+            Assert.Equal("timeout", tracker.HelloOutcome);
+        }
+
+        private static HelloTracker NewTracker(TempDirectory tmp, FakeSignalIngressSink ingress, int helloWaitTimeoutSeconds) =>
+            new HelloTracker(
+                sessionId: "S1",
+                tenantId: "T1",
+                post: new InformationalEventPost(ingress, new VirtualClock(Fixed)),
+                logger: new AgentLogger(tmp.Path, AgentLogLevel.Info),
+                helloWaitTimeoutSeconds: helloWaitTimeoutSeconds);
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogPatternPackLinearityTests.cs

@@ -337,7 +337,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
                 "Launch powershell executor in machine session",
                 new[] { "context=machine" }
             };
-            // Wording from the IME decompile (ContentDownloaderDeliveryOptimization, identical 1.97–1.105).
+            // IME wording, identical from 1.97 to 1.105.
             yield return new object[]
             {
                 "IME-DO-TIMEOUT-2",

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerHealthTests.cs

@@ -140,6 +140,22 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
             Assert.Equal(1, fired); // the persisted flag suppressed the second emission
         }
 
+        [Fact]
+        public void Registry_reconciliation_counters_survive_a_restart()
+        {
+            using var h = new Harness();
+            h.Tracker.ScriptRuns.CountVerified();
+            h.Tracker.ScriptRuns.CountVerified();
+            h.Tracker.ScriptRuns.CountCorrected();
+            h.Tracker.SaveStateForTest();
+
+            h.Restart();
+
+            var health = h.Tracker.GetHealthSnapshot();
+            Assert.Equal(2, health.PlatformOutputVerified);
+            Assert.Equal(1, health.PlatformOutputCorrected);
+        }
+
         [Fact]
         public async Task Handler_time_does_not_count_against_the_line_budget()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerOverwriteRewindTests.RetryPairing.cs

@@ -0,0 +1,336 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// B-96m: IME re-runs a failed platform script on later check-ins, so AgentExecutor.log can hold several runs of one
+    /// policy before the tracker has read IME's result of the first — always on the agent's first pass (the agent starts
+    /// mid-enrollment and reads all of AgentExecutor.log before IntuneManagementExtension.log), after a restart, and
+    /// whenever a result line surfaces late. With one slot per policy the second executor start reused the first run's
+    /// slot and its end block overwrote the first one: the first IME result went out with the LAST run's exit code and
+    /// output (session eff1b413: the bootstrap script "Failed (exit 0)" with the stdout of its successful retry), every
+    /// later result without an end block. These tests pin one run per executor start, each IME result paired with the
+    /// run of its policy that started last before it, each run carrying its own end block.
+    /// </summary>
+    public sealed partial class ImeLogTrackerOverwriteRewindTests
+    {
+        private const string RetryPolicyId = "4c2d8e1a-7b3f-4a9e-8d21-6f0b5c3e9a74";
+        private const string RetryUser = "00000000-0000-0000-0000-000000000000";
+
+        private static string ImeEntryAt(string time, string message)
+            => $"<![LOG[{message}]LOG]!><time=\"{time}\" date=\"9-10-2026\" component=\"IntuneManagementExtension\" context=\"\" type=\"1\" thread=\"12\" file=\"\">\r\n";
+
+        /// <summary>One executor run's start block: banner, the platform argument line, paths, launch.</summary>
+        private static string RunStart(string time, string pid, string policyId = RetryPolicyId, string userId = RetryUser)
+        {
+            var path = $@"{ImeDir}\Policies\Scripts\{userId}_{policyId}.ps1";
+            var results = $@"{ImeDir}\Policies\Results\{userId}_{policyId}";
+            return ExecutorBanner(time)
+                + EntryAt(time, $"Adding argument powershell with value {path} to the named argument list.")
+                + EntryAt(time, "Powershell option gets invoked")
+                + EntryAt(time, path)
+                + EntryAt(time, results + ".output")
+                + EntryAt(time, results + ".error")
+                + EntryAt(time, results + ".timeout")
+                + ExecutorLaunch(time, path, pid);
+        }
+
+        /// <summary>
+        /// One executor run's end block in AgentExecutor's order. "error from script =" logs the stderr buffer before the
+        /// output readers finished (<paramref name="stderrSnapshot"/>); "write output done" logs the final texts, the
+        /// error part being exactly the error file IME judges.
+        /// </summary>
+        private static string RunEnd(string time, int exitCode, string stdout, string stderr, string? stderrSnapshot = null)
+            => EntryAt(time, $"Powershell exit code is {exitCode}")
+            + EntryAt(time, $"length of out={stdout.Length}")
+            + EntryAt(time, $"length of error={stderr.Length}")
+            + EntryAt(time, "error from script =" + (stderrSnapshot ?? stderr))
+            + EntryAt(time, exitCode == 0 ? "Powershell script is successfully executed." : "Powershell script is failed to execute")
+            + EntryAt(time, $"write output done. output = {stdout}, error = {stderr}")
+            + EntryAt(time, "Revert Wow64FsRedirection")
+            + EntryAt(time, "Agent executor completed.");
+
+        private static string ImeRunStart(string time, string policyId = RetryPolicyId, string userId = RetryUser)
+            => ImeEntryAt(time, $@"Script file {ImeDir}\Policies\Scripts\{userId}_{policyId}.ps1 is generated.");
+
+        private static string ImeRunResult(string time, string result, string policyId = RetryPolicyId, string userId = RetryUser)
+            => ImeEntryAt(time, $"[PowerShell] User Id = {userId}, Policy id = {policyId}, policy result = {result}");
+
+        private static void AppendImeLog(Harness h, string text)
+            => File.AppendAllText(Path.Combine(Path.GetDirectoryName(h.LogPath)!, "IntuneManagementExtension.log"), text, new UTF8Encoding(false));
+
+        /// <summary>Result | exit | stdout | stderr — readable in an assertion failure; "-" no exit code, "~" never read.</summary>
+        private static string Shape(ScriptExecutionState s)
+            => $"{s.Result}|{(s.ExitCode.HasValue ? s.ExitCode.Value.ToString() : "-")}|{s.Stdout ?? "~"}|{s.Stderr ?? "~"}";
+
+        /// <summary>
+        /// Two poll passes as the agent runs them (read the files, then the flushes), the second past the result hold:
+        /// a result missing its end block goes out by then.
+        /// </summary>
+        private static async Task PassAndSettle(Harness h)
+        {
+            await h.Tracker.RunPollPassAsync(default);
+            h.Now = h.Now.AddSeconds(6);
+            await h.Tracker.RunPollPassAsync(default);
+        }
+
+        [Fact]
+        public async Task First_pass_pairs_each_ime_result_with_the_end_block_of_its_own_run()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            // IME's first run and two retries on later check-ins, all written before the agent started.
+            h.Append(RunStart("12:00:10.0000000", "1001") + RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "1002") + RunEnd("12:10:12.0000000", 1, "Run B output", "")
+                + RunStart("12:20:10.0000000", "1003") + RunEnd("12:20:12.0000000", 0, "Run C output", ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success")
+                + ImeRunStart("12:20:08.0000000") + ImeRunResult("12:20:12.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|1||Run A failed", "Success|1|Run B output|", "Success|0|Run C output|" },
+                h.Completed.Select(Shape).ToArray());
+            Assert.All(h.Completed, s => Assert.Equal("ime_policy_result", s.ResultSource));
+            Assert.True(h.Completed[0].StartedAtUtc < h.Completed[1].StartedAtUtc && h.Completed[1].StartedAtUtc < h.Completed[2].StartedAtUtc);
+            Assert.Equal(3, h.Completed.Select(s => s.RunId).Distinct().Count());
+        }
+
+        [Fact]
+        public async Task Retry_of_the_bootstrap_script_never_lends_its_success_output_to_the_failed_first_attempt()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "2001") + RunEnd("12:00:20.0000000", 1, "attempt 1: download failed", "Invoke-WebRequest : The remote name could not be resolved")
+                + RunStart("12:10:10.0000000", "2002") + RunEnd("12:10:20.0000000", 0, "===== Bootstrap Completed Successfully =====", ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:20.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:20.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[]
+            {
+                "Failed|1|attempt 1: download failed|Invoke-WebRequest : The remote name could not be resolved",
+                "Success|0|===== Bootstrap Completed Successfully =====|",
+            }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Run_killed_at_the_timeout_reports_failed_without_the_next_runs_end_block()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            // IME killed the first executor after 1800 s: its start block is all AgentExecutor.log holds of it.
+            h.Append(RunStart("12:00:10.0000000", "3001")
+                + RunStart("12:40:10.0000000", "3002") + RunEnd("12:40:12.0000000", 0, "Run B output", ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:30:10.5000000", "Failed")
+                + ImeRunStart("12:40:08.0000000") + ImeRunResult("12:40:12.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|-|~|~", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Run_whose_result_never_surfaced_falls_back_on_imes_rule_before_the_next_run()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "4001") + RunEnd("12:00:12.0000000", 0, "Run A output", "Run A wrote an error")
+                + RunStart("12:10:10.0000000", "4002") + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            // Run A's result line was lost; run B's is there.
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|0|Run A output|Run A wrote an error", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+            Assert.Equal(new[] { "agentexecutor_fallback", "ime_policy_result" }, h.Completed.Select(s => s.ResultSource).ToArray());
+        }
+
+        [Fact]
+        public async Task Run_in_flight_survives_the_emit_of_the_run_before_it()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "5001") + RunEnd("12:00:12.0000000", 0, "Run A output", "")
+                + RunStart("12:10:10.0000000", "5002"));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Success") + ImeRunStart("12:10:08.0000000"));
+            await PassAndSettle(h);
+            h.Now = h.Now.AddSeconds(30);
+            await h.Pass();
+
+            // Run B ends minutes later.
+            h.Append(RunEnd("12:10:40.0000000", 0, "Run B output", ""));
+            AppendImeLog(h, ImeRunResult("12:10:40.1000000", "Success"));
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Success|0|Run A output|", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Shutdown_between_the_two_logs_flushes_each_run_with_its_own_end_block()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "6001") + RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "6002") + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            // The pass is cancelled after AgentExecutor.log; the shutdown flush follows.
+            await h.Pass();
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now, force: true);
+
+            h.Restart();
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success"));
+            await PassAndSettle(h);
+
+            // Each run went out with its own block and IME's verdict on it; the results read after the restart are
+            // the same runs and change nothing.
+            Assert.Equal(new[] { "Failed|1||Run A failed", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+            Assert.All(h.Completed, s => Assert.Equal("agentexecutor_fallback", s.ResultSource));
+        }
+
+        [Fact]
+        public async Task End_block_line_recovered_after_the_next_run_started_stays_with_its_own_run()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "7001"));
+            var exitLineAt = h.Length;
+            h.Append(RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "7002") + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            await h.Pass();
+
+            // A stale writer rewrites run A's exit line in place: the ledger check re-reads it behind run B's start.
+            h.Overwrite(exitLineAt, EntryAt("12:00:12.0000000", "Powershell exit code is 7"));
+            h.Tracker.RequestOverwriteCheckForTest();
+            h.Now = h.Now.AddSeconds(2);
+            await h.Pass();
+
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success"));
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|7||Run A failed", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Run_without_result_or_end_block_is_dropped_once_a_later_run_has_its_result()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9001")
+                + RunStart("12:10:10.0000000", "9002") + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+            Assert.Equal(0, h.Tracker.ParkedPlatformScriptCountForTest);
+        }
+
+        [Fact]
+        public void Reading_the_same_executor_start_line_again_never_parks_its_run()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            var line = $@"Adding argument powershell with value {ImeDir}\Policies\Scripts\{RetryUser}_{RetryPolicyId}.ps1 to the named argument list.";
+            var at = T0.AddMinutes(-30);
+
+            h.Tracker.ProcessLogMessageForTest(line, at, "AgentExecutor.log");
+            h.Tracker.ProcessLogMessageForTest(line, at, "AgentExecutor.log");
+            Assert.Equal(0, h.Tracker.ParkedPlatformScriptCountForTest);
+
+            h.Tracker.ProcessLogMessageForTest(line, at.AddMinutes(10), "AgentExecutor.log");
+            Assert.Equal(1, h.Tracker.ParkedPlatformScriptCountForTest);
+        }
+
+        [Fact]
+        public async Task Run_without_end_block_keeps_waiting_for_its_result_across_a_shutdown()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9101") + RunStart("12:40:10.0000000", "9102"));
+            await h.Pass();
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now, force: true);
+            Assert.Empty(h.Completed);
+
+            h.Restart();
+            Assert.Equal(1, h.Tracker.ParkedPlatformScriptCountForTest);
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:30:10.5000000", "Failed"));
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|-|~|~" }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Earlier_run_emitted_while_a_later_one_runs_never_takes_the_later_runs_register_entry()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9201") + RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "9202"));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed") + ImeRunStart("12:10:08.0000000"));
+            await PassAndSettle(h);
+            Assert.Single(h.Completed);
+
+            // A save of this key is the latest run's, and that one is still running.
+            h.Tracker.ScriptRuns.NotePassCompleted(h.Now);
+            Assert.Equal(PlatformRunClaim.Wait, h.Tracker.ScriptRuns.TryClaim(RetryUser, RetryPolicyId, h.Now.AddSeconds(-10), out _));
+
+            h.Append(RunEnd("12:10:40.0000000", 0, "Run B output", ""));
+            AppendImeLog(h, ImeRunResult("12:10:40.1000000", "Success"));
+            await PassAndSettle(h);
+            h.Tracker.ScriptRuns.NotePassCompleted(h.Now);
+
+            Assert.Equal(PlatformRunClaim.Claimed, h.Tracker.ScriptRuns.TryClaim(RetryUser, RetryPolicyId, h.Now.AddSeconds(-10), out var run));
+            Assert.Equal(h.Completed[1].RunId, run!.RunId);
+            Assert.Equal("Run B output", run.Stdout);
+        }
+
+        [Fact]
+        public async Task Run_of_another_user_keeps_its_own_register_entry_when_it_waited_for_its_result()
+        {
+            const string otherUser = "2b7e5c91-3d4a-4f80-b6e2-9a1c7d3f5e08";
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9301") + RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "9302", userId: otherUser));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000", userId: otherUser));
+            await PassAndSettle(h);
+            h.Tracker.ScriptRuns.NotePassCompleted(h.Now);
+
+            Assert.Equal(PlatformRunClaim.Claimed, h.Tracker.ScriptRuns.TryClaim(RetryUser, RetryPolicyId, h.Now.AddSeconds(-10), out var run));
+            Assert.Equal(h.Completed[0].RunId, run!.RunId);
+            Assert.Equal(PlatformRunClaim.Wait, h.Tracker.ScriptRuns.TryClaim(otherUser, RetryPolicyId, h.Now.AddSeconds(-10), out _));
+        }
+
+        [Fact]
+        public async Task Start_line_read_again_stays_a_late_line_after_an_earlier_run_of_another_user_went_out()
+        {
+            const string otherUser = "2b7e5c91-3d4a-4f80-b6e2-9a1c7d3f5e08";
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9401") + RunEnd("12:00:12.0000000", 0, "Run A output", "")
+                + RunStart("12:10:10.0000000", "9402", userId: otherUser) + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            // Run A's result surfaces after run B's (its line was hidden by a concurrent writer).
+            AppendImeLog(h, ImeRunResult("12:10:12.1000000", "Success", userId: otherUser) + ImeRunResult("12:00:12.1000000", "Success"));
+            await PassAndSettle(h);
+            Assert.Equal(new[] { "Success|0|Run B output|", "Success|0|Run A output|" }, h.Completed.Select(Shape).ToArray());
+
+            // Run B's executor start line read again (a rewind): a late line of the emitted run B, never a new run.
+            var started = 0;
+            h.Tracker.OnScriptStarted = _ => started++;
+            h.Tracker.ProcessLogMessageForTest(
+                $@"Adding argument powershell with value {ImeDir}\Policies\Scripts\{otherUser}_{RetryPolicyId}.ps1 to the named argument list.",
+                h.Completed[0].StartedAtUtc, "AgentExecutor.log");
+            Assert.Equal(0, started);
+        }
+
+        [Fact]
+        public async Task Final_stderr_of_the_end_block_replaces_the_early_snapshot_even_without_stdout()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            // The snapshot was taken before the error reader finished; IME judged the full error file.
+            h.Append(RunStart("12:00:10.0000000", "8001") + RunEnd("12:00:12.0000000", 0, "", "Remove-AppxPackage : Cannot process argument", stderrSnapshot: ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|0||Remove-AppxPackage : Cannot process argument" }, h.Completed.Select(Shape).ToArray());
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerOverwriteRewindTests.RewindFreshness.cs

@@ -0,0 +1,139 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.SignalAdapters;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// Sessions d29e27e3 and 4377911b: a concurrent IME writer overwrote the result line of a platform script, and the
+    /// overwrite check recovered it one pass later. Recovered lines were never fresh, so they resolved in the agent's own
+    /// cached zone (+60) instead of anchoring themselves (+120): the end stamp landed an hour ahead of the clock and the
+    /// run duration was omitted. Bytes that read differently at a position than at the last look were written after that
+    /// look, so when the replaced bytes were confirmed seconds ago the new line's age is bounded like an appended line's —
+    /// these tests pin that it anchors itself then, and only then.
+    /// </summary>
+    public sealed partial class ImeLogTrackerOverwriteRewindTests
+    {
+        private static void AppendExecutorLog(Harness h, string text)
+            => File.AppendAllText(Path.Combine(Path.GetDirectoryName(h.LogPath)!, "AgentExecutor.log"), text, new UTF8Encoding(false));
+
+        /// <summary>An IME log entry with the byte length of <paramref name="sameLengthAs"/>: what a stale writer's line replaces exactly.</summary>
+        private static string FillerLike(string time, string sameLengthAs)
+        {
+            var bare = ImeEntryAt(time, "[Win32App] checking ");
+            Assert.True(sameLengthAs.Length > bare.Length);
+            return ImeEntryAt(time, "[Win32App] checking " + new string('x', sameLengthAs.Length - bare.Length));
+        }
+
+        /// <summary>
+        /// A platform run whose IME writer lives in +120 (local = UTC + 2 h; the harness clock is 19:30Z): both logs are
+        /// observed empty first, so what follows is read fresh. Returns the IME log position where the filler line sits.
+        /// </summary>
+        private static async Task<long> StartRunAndReadFiller(Harness h, string fillerTime, string resultEntry)
+        {
+            h.Append(string.Empty);
+            AppendExecutorLog(h, string.Empty);
+            await h.Tracker.RunPollPassAsync(default);
+
+            AppendExecutorLog(h, RunStart("21:29:50.0000000", "1001"));
+            h.Append(ImeRunStart("21:29:48.0000000"));
+            await h.Tracker.RunPollPassAsync(default);
+
+            // Another IME writer appends a line; the tracker reads it.
+            var at = h.Length;
+            h.Append(FillerLike(fillerTime, resultEntry));
+            h.Now = h.Now.AddSeconds(1);
+            await h.Tracker.RunPollPassAsync(default);
+            return at;
+        }
+
+        [Fact]
+        public async Task Result_line_recovered_seconds_after_its_bytes_were_read_anchors_itself_like_a_fresh_line()
+        {
+            using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            var result = ImeRunResult("21:30:01.1000000", "Success");
+            var at = await StartRunAndReadFiller(h, "21:30:00.5000000", result);
+
+            // The script ends: its end block, then the stale IME service writes the result over the filler.
+            AppendExecutorLog(h, RunEnd("21:30:01.0000000", 0, "done", ""));
+            h.Overwrite(at, result);
+            h.Now = h.Now.AddSeconds(1);
+            await PassAndSettle(h);
+
+            Assert.Equal(1, h.Health.OverwriteRewinds);
+            var script = Assert.Single(h.Completed);
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, script.ResultProvenance!.Origin);
+            Assert.Equal(120, script.ResultProvenance.OffsetMinutes);
+            Assert.Equal(ImeLogTrackerAdapter.DurationPairVerdict.Verified, ImeLogTrackerAdapter.JudgeDurationPair(
+                script.StartedAtProvenance, script.ResultProvenance, false, script.ResultObservedAtUtc!.Value - script.StartedAtUtc!.Value, out _));
+        }
+
+        [Fact]
+        public async Task Verification_passes_keep_the_replaced_bytes_current_for_a_script_that_runs_longer()
+        {
+            using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            var result = ImeRunResult("21:30:41.1000000", "Success");
+            var at = await StartRunAndReadFiller(h, "21:30:00.5000000", result);
+
+            // The script runs 40 s; the cadence check verifies the ledger every 10 s while the run is in flight.
+            for (var i = 0; i < 4; i++)
+            {
+                h.Now = h.Now.AddSeconds(10);
+                await h.Tracker.RunPollPassAsync(default);
+            }
+
+            AppendExecutorLog(h, RunEnd("21:30:41.0000000", 0, "done", ""));
+            h.Overwrite(at, result);
+            h.Now = h.Now.AddSeconds(1);
+            await PassAndSettle(h);
+
+            var script = Assert.Single(h.Completed);
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, script.ResultProvenance!.Origin);
+            Assert.Equal(120, script.ResultProvenance.OffsetMinutes);
+        }
+
+        [Fact]
+        public async Task Overwrite_does_not_move_the_files_measured_writer_offset()
+        {
+            using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            var result = ImeRunResult("21:30:01.1000000", "Success");
+            var at = await StartRunAndReadFiller(h, "21:30:00.5000000", result);
+            Assert.True(h.Tracker.OffsetCalibrator.TryGetOffset("IntuneManagementExtension.log", out var before));
+
+            AppendExecutorLog(h, RunEnd("21:30:01.0000000", 0, "done", ""));
+            h.Overwrite(at, result);
+            h.Now = h.Now.AddSeconds(1);
+            await PassAndSettle(h);
+
+            Assert.True(h.Tracker.OffsetCalibrator.TryGetOffset("IntuneManagementExtension.log", out var after));
+            Assert.Equal(before, after);
+        }
+
+        [Theory]
+        // Replaced bytes confirmed 1 s / 30 s ago: written since, age bounded like an appended line's.
+        [InlineData(true, true, 1, true)]
+        [InlineData(true, true, 30, true)]
+        // Confirmed longer ago: the new bytes could be minutes old — their age may round onto the 15-minute grid.
+        [InlineData(true, true, 31, false)]
+        // The clock stepped back since the confirmation: the age is unknown.
+        [InlineData(true, true, -1, false)]
+        // The divergence lies in bytes the ledger never held (dropped by a cap): nothing dates them.
+        [InlineData(true, false, 1, false)]
+        // The pass itself is not fresh — the first pass after a restart never anchors.
+        [InlineData(false, true, 1, false)]
+        // Nothing was replaced.
+        [InlineData(true, true, null, false)]
+        public void Rewound_entry_is_fresh_only_when_the_bytes_it_replaced_were_confirmed_within_the_fresh_window(
+            bool passLinesAreFresh, bool entryAtRewindPointReplaced, int? secondsSinceConfirmed, bool expected)
+        {
+            var now = new DateTime(2026, 10, 4, 19, 2, 0, DateTimeKind.Utc);
+            DateTime? confirmed = secondsSinceConfirmed.HasValue ? now.AddSeconds(-secondsSinceConfirmed.Value) : (DateTime?)null;
+            Assert.Equal(expected, ImeLogTracker.RewoundEntryIsFresh(passLinesAreFresh, entryAtRewindPointReplaced, confirmed, now));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerOverwriteRewindTests.WriterBoundary.cs

@@ -0,0 +1,368 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// Session 756970cf: IME launched a Win32 detection executor and a platform-script executor 15 ms apart, and both
+    /// opened AgentExecutor.log at the same end-of-file offset. The platform executor's shorter start block overwrote
+    /// the detection executor's, whose identity line the tracker never saw; the detection's end block (exit 1 and its
+    /// stdout), written at its own position behind its own start block, then sat behind the PLATFORM start block, and
+    /// "the nearest preceding marker owns the line" handed another script's output and exit code to the platform
+    /// script. These tests pin the writer boundary: an entry that is not exactly one CMTrace record is where one
+    /// writer's bytes end and another's begin, and nothing behind it belongs to the invocation in front of it.
+    /// </summary>
+    public sealed partial class ImeLogTrackerOverwriteRewindTests
+    {
+        private const string RaceUserId = "00000000-0000-0000-0000-000000000000";
+        private const string RacePlatformId = "1d6f0a52-3c4e-4b7a-9e21-5f8c7d2b9a10";
+        private const string RaceDetectionAppId = "8b2e4c71-6a9d-4f03-b5e8-2c7a1d9f4e36";
+        private const string RaceFillerAppId = "5e1c2b7d-0a4f-4c8e-9d36-7b2f1e8a4c50";
+        private const string ImeDir = @"C:\Program Files (x86)\Microsoft Intune Management Extension";
+        private const string DetectionStdout = "VERBOSE: === Sample Suite Detection Started ===\r\nWARNING: === DETECTION FAILED: Sample Suite is not installed ===";
+        private const string PlatformStdout = "=== bootstrap loader started ===\r\nInstaller finished (exit code 0).";
+
+        private static string EntryAt(string time, string message)
+            => $"<![LOG[{message}]LOG]!><time=\"{time}\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">\r\n";
+
+        /// <summary>The four lines every AgentExecutor invocation starts with — identical length for every executor.</summary>
+        private static string ExecutorBanner(string time)
+            => EntryAt(time, "ExecutorLog AgentExecutor gets invoked")
+            + EntryAt(time, "Creating command line parser, name delimiter is - and value separator is  .")
+            + EntryAt(time, "Getting Ordered Parameters")
+            + EntryAt(time, "Parsing Ordered Parameters.");
+
+        private static string ExecutorLaunch(string time, string scriptPath, string pid)
+            => EntryAt(time, "Prepare to run Powershell Script ..")
+            + EntryAt(time, $"cmd line for running powershell is -NoProfile -executionPolicy bypass -file  \"{scriptPath}\" ")
+            + EntryAt(time, "runAs32BitOn64 = False, so Disable Wow64FsRedirection")
+            + EntryAt(time, @"PowerShell path is C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe")
+            + EntryAt(time, $"[Executor] created powershell with process id {pid}");
+
+        private static string PlatformStartBlock(string time, string policyId, string pid)
+        {
+            var path = $@"{ImeDir}\Policies\Scripts\{RaceUserId}_{policyId}.ps1";
+            var results = $@"{ImeDir}\Policies\Results\{RaceUserId}_{policyId}";
+            return ExecutorBanner(time)
+                + EntryAt(time, $"Adding argument powershell with value {path} to the named argument list.")
+                + EntryAt(time, "Powershell option gets invoked")
+                + EntryAt(time, path)
+                + EntryAt(time, results + ".output")
+                + EntryAt(time, results + ".error")
+                + EntryAt(time, results + ".timeout")
+                + ExecutorLaunch(time, path, pid);
+        }
+
+        private static string DetectionStartBlock(string time, string appId, string pid)
+        {
+            var path = $@"{ImeDir}\Content\DetectionScripts\{appId}_2.ps1";
+            return ExecutorBanner(time)
+                + EntryAt(time, $"Adding argument powershellDetection with value {path} to the named argument list.")
+                + EntryAt(time, "PowershellDetection option gets invoked")
+                + EntryAt(time, path)
+                + EntryAt(time, path + "quotedResultFilePath.txt")
+                + EntryAt(time, path + "quotedErrorFilePath.txt")
+                + EntryAt(time, path + "quotedTimeoutFilePath.txt")
+                + EntryAt(time, path + "quotedExitCodeFilePath.txt")
+                + ExecutorLaunch(time, path, pid);
+        }
+
+        private static string ExecutorEndBlock(string time, int exitCode, string stdout)
+            => EntryAt(time, $"Powershell exit code is {exitCode}")
+            + EntryAt(time, $"length of out={stdout.Length}")
+            + EntryAt(time, "length of error=0")
+            + EntryAt(time, "error from script =")
+            + EntryAt(time, exitCode == 0 ? "Powershell script is successfully executed." : "Powershell script is failed to execute")
+            + EntryAt(time, $"write output done. output = {stdout}, error = ")
+            + EntryAt(time, "Revert Wow64FsRedirection")
+            + EntryAt(time, "Agent executor completed.");
+
+        private static string PlatformResultLine(string policyId)
+            => $"[PowerShell] User Id = {RaceUserId}, Policy id = {policyId}, policy result = Success";
+
+        /// <summary>The file offsets at which the entries of an ASCII <paramref name="block"/> start when it is written at <paramref name="at"/>.</summary>
+        private static HashSet<long> EntryStarts(string block, long at)
+        {
+            Assert.True(block.All(c => c < 128), "offset arithmetic assumes ASCII test content");
+            var starts = new HashSet<long>();
+            for (var i = block.IndexOf("<![LOG[", StringComparison.Ordinal); i >= 0; i = block.IndexOf("<![LOG[", i + 1, StringComparison.Ordinal))
+                starts.Add(at + i);
+            return starts;
+        }
+
+        [Fact]
+        public async Task Executor_that_opened_at_the_same_offset_never_lends_its_end_block_to_the_platform_script()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+
+            // An earlier, finished detection run: the race starts mid-file like in the field log.
+            h.Append(DetectionStartBlock("12:00:00.0000000", RaceFillerAppId, "1548") + ExecutorEndBlock("12:00:00.5000000", 0, "detected"));
+            await h.Pass();
+            var x = h.Length;
+
+            // Detection executor C and platform executor D open the file at the same end x. C writes first; the tracker
+            // reads C's banner, then D writes its own start block over C's.
+            var cStart = DetectionStartBlock("12:00:01.0000000", RaceDetectionAppId, "6416");
+            var dStart = PlatformStartBlock("12:00:01.2000000", RacePlatformId, "2524");
+            var cHead = cStart.Substring(0, cStart.IndexOf("<![LOG[Getting Ordered Parameters", StringComparison.Ordinal));
+            h.Append(cHead);
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+            h.Append(cStart.Substring(cHead.Length));
+            h.Overwrite(x, dStart);
+
+            // The field geometry: D's start block is shorter and ends inside one of C's lines, so the tail of that line
+            // sits between D's start block and C's remaining bytes.
+            Assert.True(dStart.Length < cStart.Length);
+            Assert.DoesNotContain(x + dStart.Length, EntryStarts(cStart, x));
+            h.Now = h.Now.AddMilliseconds(150);
+            await h.Pass();
+            Assert.True(h.Health.OverwriteRewinds >= 1);
+
+            // C ends: its end block lands at its own position, right behind its own (overwritten) start block.
+            Assert.Equal(x + cStart.Length, h.Length);
+            var cEnd = ExecutorEndBlock("12:00:07.0000000", 1, DetectionStdout);
+            h.Append(cEnd);
+            h.Now = h.Now.AddSeconds(6);
+            await h.Pass();
+
+            // IME's result for D reaches the tracker before D's own end block: the completion must wait for it.
+            h.Tracker.ProcessLogMessageForTest(PlatformResultLine(RacePlatformId), sourceFileName: "IntuneManagementExtension.log");
+            Assert.Empty(h.Completed);
+
+            // D ends: its end block lands at ITS position, over the fragment and C's bytes; C's last line survives.
+            var dEnd = ExecutorEndBlock("12:00:09.5000000", 0, PlatformStdout);
+            Assert.True(dEnd.Length < cStart.Length - dStart.Length + cEnd.Length);
+            h.Overwrite(x + dStart.Length, dEnd);
+            h.Now = h.Now.AddMilliseconds(130);
+            await h.Pass();
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now);
+
+            var script = Assert.Single(h.Completed);
+            Assert.Equal(RacePlatformId, script.PolicyId);
+            Assert.Equal("Success", script.Result);
+            Assert.Equal(0, script.ExitCode);
+            Assert.Equal(PlatformStdout.Replace("\r\n", "\n"), script.Stdout);
+            Assert.DoesNotContain(h.Completed, s => (s.Stdout ?? string.Empty).Contains("Detection"));
+
+            // The run is known to the registry reconciliation under the user id of its own lines (D-316).
+            Assert.Equal(RaceUserId, script.UserId);
+            Assert.False(string.IsNullOrEmpty(script.RunId));
+            h.Tracker.ScriptRuns.NotePassCompleted(DateTime.MaxValue.AddDays(-1));
+            Assert.Equal(PlatformRunClaim.Claimed, h.Tracker.ScriptRuns.TryClaim(RaceUserId, RacePlatformId, h.Now, out var run));
+            Assert.Equal(script.RunId, run!.RunId);
+        }
+
+        /// <summary>
+        /// The mirror image: a foreign executor whose stream position lies inside the platform start block (it opened
+        /// at the same end with a shorter start block) writes its end block there. Its first line merges with the head of
+        /// a platform line — cut inside the message or inside the trailer, which the parser would otherwise read up to
+        /// the foreign trailer — and its output line follows without any marker in between.
+        /// </summary>
+        [Theory]
+        [InlineData(15)]
+        [InlineData(-30)]
+        public async Task Foreign_end_block_merged_into_the_platform_start_block_never_reaches_the_platform_script(int cut)
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(DetectionStartBlock("12:00:00.0000000", RaceFillerAppId, "1548") + ExecutorEndBlock("12:00:00.5000000", 0, "detected"));
+            await h.Pass();
+            var x = h.Length;
+
+            var dStart = PlatformStartBlock("12:00:01.0000000", RacePlatformId, "2524");
+            h.Append(dStart);
+            await h.Pass();
+
+            // The foreign end block starts inside the line after D's argument line.
+            var lineAfterArgument = x + dStart.IndexOf("<![LOG[Powershell option gets invoked", StringComparison.Ordinal);
+            var lineLength = EntryAt("12:00:01.0000000", "Powershell option gets invoked").Length;
+            var at = lineAfterArgument + (cut > 0 ? cut : lineLength + cut);
+            var foreignEnd = ExecutorEndBlock("12:00:03.0000000", 1, "foreign output");
+            Assert.True(at + foreignEnd.Length < x + dStart.Length, "the foreign block must end inside D's start block");
+            h.Overwrite(at, foreignEnd);
+            h.Tracker.RequestOverwriteCheckForTest();
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+
+            h.Tracker.ProcessLogMessageForTest(PlatformResultLine(RacePlatformId), sourceFileName: "IntuneManagementExtension.log");
+            h.Now = h.Now.Add(ImeLogTracker.PlatformScriptEndBlockGrace);
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now);
+
+            // No owner is provable behind the cut: the completion goes out without end-block data, never with the foreign one.
+            var script = Assert.Single(h.Completed);
+            Assert.Equal("Success", script.Result);
+            Assert.Null(script.ExitCode);
+            Assert.Null(script.Stdout);
+        }
+
+        [Fact]
+        public async Task Entry_read_unchanged_after_a_rewind_keeps_its_platform_marker()
+        {
+            const string platformId = "2b7d9e41-8c3a-4f60-a5d2-9e1b7c4f3a08";
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+
+            // Detection W waits for its script; detection X runs completely behind it; platform F starts behind X.
+            var wStart = DetectionStartBlock("12:00:00.0000000", RaceFillerAppId, "1111");
+            var xRun = DetectionStartBlock("12:00:00.2000000", RaceDetectionAppId, "2222") + ExecutorEndBlock("12:00:00.4000000", 0, "x detected");
+            h.Append(wStart + xRun + PlatformStartBlock("12:00:01.0000000", platformId, "3333"));
+            await h.Pass();
+
+            // W ends at its own position, over the head of X's run; F's start block keeps its bytes and offset.
+            var wEnd = ExecutorEndBlock("12:00:02.0000000", 0, "w detected");
+            Assert.True(wEnd.Length < xRun.Length);
+            h.Overwrite(wStart.Length, wEnd);
+            h.Tracker.RequestOverwriteCheckForTest();
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+            Assert.Equal(1, h.Health.OverwriteRewinds);
+
+            // F's end block lands behind its start block: still F's, because F's marker survived with its bytes.
+            h.Append(ExecutorEndBlock("12:00:05.0000000", 7, "Hello from F"));
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+            h.Tracker.ProcessLogMessageForTest(PlatformResultLine(platformId), sourceFileName: "IntuneManagementExtension.log");
+
+            var script = Assert.Single(h.Completed);
+            Assert.Equal(platformId, script.PolicyId);
+            Assert.Equal(7, script.ExitCode);
+            Assert.Equal("Hello from F", script.Stdout);
+        }
+
+        [Fact]
+        public async Task Writer_boundary_read_unchanged_after_a_rewind_still_closes_the_platform_invocation()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+
+            // Detection Q waits for its script while detection R runs completely behind it.
+            var qStart = DetectionStartBlock("12:00:00.0000000", RaceFillerAppId, "1111");
+            var rRun = DetectionStartBlock("12:00:00.2000000", "6c3f8a20-1d5e-4b97-8f4a-0e2d6b9c7a13", "2222") + ExecutorEndBlock("12:00:00.4000000", 0, "r detected");
+            h.Append(qStart + rRun);
+            await h.Pass();
+            var x = h.Length;
+
+            // The race of the field case behind them: the boundary closes D.
+            var cStart = DetectionStartBlock("12:00:01.0000000", RaceDetectionAppId, "6416");
+            var dStart = PlatformStartBlock("12:00:01.2000000", RacePlatformId, "2524");
+            h.Append(cStart);
+            h.Overwrite(x, dStart);
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+
+            // Q ends at its own position, over R's run: the rewind starts in front of the race, whose bytes read unchanged.
+            var qEnd = ExecutorEndBlock("12:00:02.0000000", 0, "q detected");
+            Assert.True(qEnd.Length < rRun.Length);
+            h.Overwrite(qStart.Length, qEnd);
+            h.Tracker.RequestOverwriteCheckForTest();
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+
+            // C's end block behind the boundary stays unowned; D's own end block completes D.
+            var cEnd = ExecutorEndBlock("12:00:07.0000000", 1, DetectionStdout);
+            h.Append(cEnd);
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+            h.Tracker.ProcessLogMessageForTest(PlatformResultLine(RacePlatformId), sourceFileName: "IntuneManagementExtension.log");
+            Assert.Empty(h.Completed);
+
+            h.Overwrite(x + dStart.Length, ExecutorEndBlock("12:00:09.5000000", 0, PlatformStdout));
+            h.Now = h.Now.AddMilliseconds(130);
+            await h.Pass();
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now);
+
+            var script = Assert.Single(h.Completed);
+            Assert.Equal(0, script.ExitCode);
+            Assert.Equal(PlatformStdout.Replace("\r\n", "\n"), script.Stdout);
+        }
+
+        [Fact]
+        public async Task Raw_text_in_the_executor_log_is_never_matched_and_closes_the_platform_invocation()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(PlatformStartBlock("12:00:00.0000000", RacePlatformId, "2524"));
+            await h.Pass();
+
+            // The tail of a cut line that happens to read like an exit line, then a foreign end block.
+            h.Append("Powershell exit code is 5\r\n" + ExecutorEndBlock("12:00:02.0000000", 6, "foreign output"));
+            // A fragment right at the bookmark stops the first pass for a check; the second one reads it.
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+
+            h.Tracker.ProcessLogMessageForTest(PlatformResultLine(RacePlatformId), sourceFileName: "IntuneManagementExtension.log");
+            h.Now = h.Now.Add(ImeLogTracker.PlatformScriptEndBlockGrace);
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now);
+
+            var script = Assert.Single(h.Completed);
+            Assert.Null(script.ExitCode);
+            Assert.Null(script.Stdout);
+        }
+
+        [Fact]
+        public async Task Fragment_in_the_ime_log_does_not_close_the_platform_run_context()
+        {
+            using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            // In the IME log the service writes the platform marker and the context line itself; the fragment in
+            // between is the tail of an executor's telemetry line and separates nothing.
+            h.Append(Entry(@"Script file C:\Program Files (x86)\Microsoft Intune Management Extension\Policies\Scripts\" + RaceUserId + "_" + RacePlatformId + ".ps1 is generated.", "17")
+                + "ing mananger...]LOG]!><time=\"12:00:00.0000000\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">\r\n"
+                + Entry("Launch powershell executor in user session", "17"));
+            await h.Pass();
+
+            h.Tracker.ProcessLogMessageForTest(PlatformResultLine(RacePlatformId));
+            h.Now = h.Now.Add(ImeLogTracker.PlatformScriptEndBlockGrace);
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now);
+
+            var script = Assert.Single(h.Completed);
+            Assert.Equal("User", script.RunContext);
+        }
+
+        [Fact]
+        public async Task Cut_multi_line_output_adds_one_boundary_not_one_per_line()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(PlatformStartBlock("12:00:00.0000000", RacePlatformId, "2524"));
+            await h.Pass();
+            var markersBefore = h.Tracker.InvocationMarkerCountForTest("AgentExecutor.log");
+
+            var lines = string.Concat(Enumerable.Range(1, 600).Select(i => $"orphaned output line {i}\r\n"));
+            h.Append(lines);
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+            h.Now = h.Now.AddMilliseconds(100);
+            await h.Pass();
+
+            Assert.Equal(markersBefore + 1, h.Tracker.InvocationMarkerCountForTest("AgentExecutor.log"));
+        }
+
+        [Theory]
+        [InlineData("<![LOG[Powershell exit code is 0]LOG]!><time=\"12:00:00.0000000\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">", true)]
+        [InlineData("<![LOG[write output done. output = line one\nline two, error = ]LOG]!><time=\"12:00:00.0000000\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">", true)]
+        [InlineData("\uFEFF<![LOG[ExecutorLog AgentExecutor gets invoked]LOG]!><time=\"12:00:00.0000000\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">", true)]
+        [InlineData("t code is 3]LOG]!><time=\"12:00:00.0000000\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">", false)]
+        [InlineData("", false)]
+        [InlineData("<![LOG[Powe<![LOG[Powershell exit code is 1]LOG]!><time=\"12:00:00.0000000\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">", false)]
+        [InlineData("<![LOG[Powershell option gets invoked]LOG]!><time=\"12:00:00.0000000\" da<![LOG[Powershell exit code is 1]LOG]!><time=\"12:00:01.0000000\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">", false)]
+        [InlineData("<![LOG[write output done. output = line one\nline<![LOG[Agent executor completed.]LOG]!><time=\"12:00:00.0000000\" date=\"9-10-2026\" component=\"AgentExecutor\" context=\"\" type=\"1\" thread=\"1\" file=\"\">", false)]
+        public void Single_cmtrace_record_is_told_apart_from_the_cut_of_two_writers(string text, bool expected)
+        {
+            Assert.Equal(expected, ImeLogTracker.IsSingleCmTraceRecord(text));
+        }
+
+        [Theory]
+        [InlineData("AgentExecutor.log", true)]
+        [InlineData("AgentExecutor-20261003-233348.log", true)]
+        [InlineData("IntuneManagementExtension.log", false)]
+        [InlineData("IntuneManagementExtension-20261003-233348.log", false)]
+        [InlineData("HealthScripts.log", false)]
+        [InlineData("AppWorkload.log", false)]
+        public void Writer_boundaries_apply_to_the_executor_log_live_and_rotated(string fileName, bool expected)
+        {
+            Assert.Equal(expected, ImeLogTracker.IsWriterBoundaryLogFile(fileName));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerOverwriteRewindTests.cs

@@ -25,7 +25,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
     /// contract: unchanged bytes never rewind, changed bytes are processed exactly once, and the
     /// executor lines a rewind uncovers belong to the invocation that owns their file position.
     /// </summary>
-    public sealed class ImeLogTrackerOverwriteRewindTests
+    public sealed partial class ImeLogTrackerOverwriteRewindTests
     {
         private static readonly DateTime T0 = new DateTime(2026, 9, 10, 19, 30, 0, DateTimeKind.Utc);
 
@@ -42,7 +42,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
         private static readonly string[] ScriptPatternIds =
         {
             "PS-AGENT-INVOCATION", "PS-AGENT-ARG", "PS-AGENT-SCRIPT-START", "PS-AGENT-EXITCODE",
-            "PS-AGENT-OUTPUT", "PS-AGENT-COMPLETED", "PS-SCRIPT-GENERATED", "PS-SCRIPT-CONTEXT", "PS-SCRIPT-RESULT",
+            "PS-AGENT-OUTPUT", "PS-AGENT-ERROR", "PS-AGENT-COMPLETED", "PS-SCRIPT-GENERATED", "PS-SCRIPT-CONTEXT", "PS-SCRIPT-RESULT",
         };
 
         /// <summary>The shipped pattern JSON — the same source combine.js embeds — so the contract is the real one.</summary>
@@ -502,6 +502,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
         public async Task Ime_result_line_hidden_by_an_executor_start_line_is_recovered_from_the_ime_log()
         {
             using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            // Seen empty first: the start lines are fresh and anchor themselves like the recovered result line will,
+            // so start and result sit on one timeline whatever the host's own zone is.
+            h.Append(string.Empty);
+            await h.Pass();
             h.Append(Entry(GeneratedLine, "17") + Entry("Launch powershell executor in user session", "17") + Entry("process id = 10608", "17"));
             await h.Pass();
             var servicePosition = h.Length;

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerPlatformScriptFallbackTests.cs

@@ -83,8 +83,33 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
             Assert.Single(emitted);
         }
 
+        [Theory]
+        // IME's verdict is Success exactly when the error file is empty, whatever the exit code. Judged by the exit
+        // code, session 67ae751c showed exit 0 with the script's own stderr as Success, and 46a41a0a an exit 1 without
+        // stderr as Failed, a run IME reported as Success one cycle earlier.
+        [InlineData(0, "Invoke-WebRequest : The remote name could not be resolved", "Failed")]
+        [InlineData(1, "", "Success")]
+        [InlineData(1, "  \n", "Success")]
+        [InlineData(0, "", "Success")]
+        [InlineData(1, null, "Failed")]
+        [InlineData(0, null, "Success")]
+        public void Fallback_judges_like_ime_by_the_stderr_it_read(int exitCode, string? stderr, string expected)
+        {
+            using var tmp = new TempDirectory();
+            var tracker = BuildTracker(tmp, out var emitted);
+            var observedAt = new DateTime(2026, 6, 19, 12, 59, 4, DateTimeKind.Utc);
+
+            tracker.SeedPendingPlatformScriptForTesting("0d2294bf", exitCode: exitCode, exitObservedAtUtc: observedAt, stderr: stderr);
+            tracker.FlushPendingPlatformScriptResults(observedAt.AddSeconds(20));
+
+            var script = Assert.Single(emitted);
+            Assert.Equal(expected, script.Result);
+            Assert.Equal(exitCode, script.ExitCode);
+            Assert.Equal("agentexecutor_fallback", script.ResultSource);
+        }
+
         [Fact]
-        public void Nonzero_exit_code_emits_failed_result()
+        public void Nonzero_exit_code_without_a_stderr_line_emits_failed_result()
         {
             using var tmp = new TempDirectory();
             var tracker = BuildTracker(tmp, out var emitted);

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerScriptStatePersistenceTests.cs

@@ -108,6 +108,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
 
             var tracker = BuildTracker(tmp, out var emitted);
             tracker.LoadStateForTest(); // must not throw
+            Assert.Equal(0, tracker.ParkedPlatformScriptCountForTest);
 
             // Degrades to pre-fix behavior: no markers restored, normal emission works (the
             // result waits for its end block until the shutdown flush).
@@ -116,6 +117,32 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
             Assert.Single(emitted);
         }
 
+        [Fact]
+        public void Pending_slot_from_a_state_file_without_executor_start_loads_and_completes()
+        {
+            using var tmp = new TempDirectory();
+            var started = new DateTime(2026, 10, 4, 9, 0, 0, DateTimeKind.Utc);
+
+            // A pending slot written by an agent before runs carried their executor start and run id.
+            var persistence = new ImeTrackerStatePersistence(tmp.Path, new AgentLogger(tmp.Path, AgentLogLevel.Info));
+            persistence.Save(new ImeTrackerStateData
+            {
+                PendingPlatformScripts = new List<ScriptExecutionState>
+                {
+                    new ScriptExecutionState { PolicyId = "policyF", ScriptType = "platform", StartedAtUtc = started, ExitCode = 0, ExitObservedAtUtc = started.AddSeconds(5), Stdout = "done", Stderr = "" },
+                },
+            });
+
+            var tracker = BuildTracker(tmp, out var emitted);
+            tracker.LoadStateForTest();
+            tracker.CompletePlatformScriptFromImeResultForTesting("policyF", "Success", started.AddSeconds(6));
+
+            var script = Assert.Single(emitted);
+            Assert.Equal("Success", script.Result);
+            Assert.Equal(0, script.ExitCode);
+            Assert.False(string.IsNullOrEmpty(script.RunId));
+        }
+
         [Fact]
         public void Stale_result_older_than_current_run_start_is_dropped()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Runtime/DiagnosticsPackageServiceTests.cs

@@ -19,6 +19,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Runtime
     /// completion markers (whiteglove.complete, clean-exit) — V1 sessions had only AgentLogs/
     /// and ImeLogs/, which left forensics blind to decision-engine state and pending uploads.
     /// </summary>
+    [Collection(UserProfileResolverCollection.Name)] // replaces UserProfileResolver's static state
     public sealed class DiagnosticsPackageServiceTests
     {
         private static AgentConfiguration Cfg(string sessionId = "S1") => new AgentConfiguration

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Runtime/UserProfileResolverTests.cs

@@ -0,0 +1,96 @@
+using System;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Runtime
+{
+    /// <summary>
+    /// Serialises the test classes that replace <see cref="UserProfileResolver"/>'s static state.
+    /// </summary>
+    [CollectionDefinition(Name)]
+    public sealed class UserProfileResolverCollection
+    {
+        public const string Name = "UserProfileResolver";
+    }
+
+    /// <summary>
+    /// The agent starts before anyone has signed in. A lookup in that window must not pin
+    /// "no user" for the rest of the process — the %LOGGED_ON_USER_PROFILE% gather rules and the
+    /// RealmJoin user logs of the diagnostics package would never resolve.
+    /// </summary>
+    [Collection(UserProfileResolverCollection.Name)]
+    public sealed class UserProfileResolverTests : IDisposable
+    {
+        private static readonly DateTime Start = new DateTime(2026, 9, 28, 12, 0, 0, DateTimeKind.Utc);
+
+        public void Dispose() => UserProfileResolver.Reset();
+
+        [Fact]
+        public void User_who_signs_in_after_the_first_lookup_is_found_later()
+        {
+            string? signedIn = null;
+            var now = Start;
+            UserProfileResolver.SetDetectorForTesting(() => signedIn, () => now);
+
+            Assert.Null(UserProfileResolver.GetLoggedOnUserProfilePath());
+
+            signedIn = @"C:\Users\enduser";
+            now += UserProfileResolver.RetryInterval;
+
+            Assert.Equal(@"C:\Users\enduser", UserProfileResolver.GetLoggedOnUserProfilePath());
+        }
+
+        [Fact]
+        public void No_user_is_detected_again_only_after_the_retry_interval()
+        {
+            var detections = 0;
+            var now = Start;
+            UserProfileResolver.SetDetectorForTesting(() => { detections++; return null; }, () => now);
+
+            UserProfileResolver.GetLoggedOnUserProfilePath();
+            now += TimeSpan.FromSeconds(10);
+            UserProfileResolver.GetLoggedOnUserProfilePath();
+            UserProfileResolver.GetLoggedOnUserProfilePath();
+            Assert.Equal(1, detections);
+
+            now += UserProfileResolver.RetryInterval;
+            UserProfileResolver.GetLoggedOnUserProfilePath();
+            Assert.Equal(2, detections);
+        }
+
+        [Fact]
+        public void A_clock_stepping_backwards_does_not_delay_the_next_detection()
+        {
+            var detections = 0;
+            var now = Start;
+            UserProfileResolver.SetDetectorForTesting(() => { detections++; return null; }, () => now);
+
+            UserProfileResolver.GetLoggedOnUserProfilePath();
+            now -= TimeSpan.FromHours(1);   // OOBE time sync
+            UserProfileResolver.GetLoggedOnUserProfilePath();
+
+            Assert.Equal(2, detections);
+        }
+
+        [Fact]
+        public void A_found_user_is_kept_without_detecting_again()
+        {
+            var detections = 0;
+            UserProfileResolver.SetDetectorForTesting(() => { detections++; return @"C:\Users\enduser"; }, () => Start);
+
+            UserProfileResolver.GetLoggedOnUserProfilePath();
+            UserProfileResolver.GetLoggedOnUserProfilePath();
+
+            Assert.Equal(1, detections);
+        }
+
+        [Fact]
+        public void Pinned_no_user_stays_null_without_real_detection()
+        {
+            UserProfileResolver.SetForTesting(null!);
+
+            Assert.Null(UserProfileResolver.GetLoggedOnUserProfilePath());
+            Assert.Null(UserProfileResolver.ExpandCustomTokens(@"%LOGGED_ON_USER_PROFILE%\AppData\Local\x.log"));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/ShellCoreTrackerBreadcrumbTests.cs

@@ -0,0 +1,445 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.Shared;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring
+{
+    /// <summary>
+    /// CloudExperienceHost navigation (D-310): one agent.log line per page start/stop and per
+    /// update-page event name, and for the OOBE update page itself (<c>OobeNDUP</c>,
+    /// <c>RebootNDUP</c>) the <c>oobe_update_page</c> telemetry plus the registry state at its live
+    /// start and stop. Descriptions follow the Shell-Core manifest templates; a 62407 value
+    /// (URLs with tenant ids) leaves the tracker only as a boolean, an integer or an HRESULT.
+    /// </summary>
+    public sealed class ShellCoreTrackerBreadcrumbTests : IDisposable
+    {
+        private static readonly DateTime At = new DateTime(2026, 10, 2, 9, 0, 0, DateTimeKind.Utc);
+
+        private const string NdupStarted = "CloudExperienceHost Web App Activity started. CXID: 'OobeNDUP'.";
+        private const string EspPageStarted = "CloudExperienceHost Web App Activity started. CXID: 'MDMProgressAfterAADRefactored'.";
+        private const string PageStopped = "CloudExperienceHost Web App Activity stopped. Result: 'success'.";
+        private const string ScanStartedName = "CloudExperienceHost Web App Event 1. Name: 'ExpeditedUpdate_startWUScanStarted'.";
+        private const string NavigateWithTenantUrl =
+            "CloudExperienceHost Web App Event 2. Name: 'Navigate', Value: '{\"httpMethod\":\"GET\",\"url\":\"https://login.microsoftonline.com/00000000-0000-0000-0000-000000000000/oauth2/authorize\"}'.";
+        private const string DownloadSucceededWithValue =
+            "CloudExperienceHost Web App Event 2. Name: 'ExpeditedUpdate_commitExpeditionDownloadInstallAsyncSucceeded', Value: '{\"url\":\"https://login.microsoftonline.com/x\"}'.";
+        private const string CspGateTrue =
+            "CloudExperienceHost Web App Event 2. Name: 'ExpeditedUpdate_isNDUPAllowedByCSPSucceeded', Value: 'true'.";
+
+        // A French Windows labels the same fields "Résultat", "Nom" and "valeur" and quotes them
+        // in guillemets; the event properties carry the values unchanged in every language.
+        private const string FrenchNdupStarted = "Activité d’application web CloudExperienceHost démarrée. CXID : « OobeNDUP ».";
+        private const string FrenchPageStopped = "Activité d’application web CloudExperienceHost arrêtée. Résultat : « success ».";
+        private const string FrenchCspGate =
+            "Événement d’application web CloudExperienceHost 2. Nom : « ExpeditedUpdate_isNDUPAllowedByCSPSucceeded », valeur : « true ».";
+
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly FakeSignalIngressSink _sink = new FakeSignalIngressSink();
+        private IReadOnlyList<OobeUpdateRegistrySnapshot.KeyState> _registry = Array.Empty<OobeUpdateRegistrySnapshot.KeyState>();
+
+        public void Dispose() => _tmp.Dispose();
+
+        private ShellCoreTracker Build(string? stateDirectory = null) =>
+            new ShellCoreTracker("S1", "T1",
+                new InformationalEventPost(_sink, new VirtualClock(At)),
+                new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                helloTracker: null,
+                oobeUpdateRegistryReader: () => _registry,
+                stateDirectory: stateDirectory);
+
+        private string StateDirectory => Path.Combine(_tmp.Path, "state");
+
+        private static void Live(ShellCoreTracker tracker, int eventId, string description, DateTime at, long recordId) =>
+            tracker.ProcessEvent(eventId, description, at, "Microsoft-Windows-Shell-Core", isBackfill: false, recordId: recordId);
+
+        private IReadOnlyList<FakeSignalIngressSink.PostedSignal> ByType(string eventType) =>
+            _sink.Posted.Where(p =>
+                p.Kind == DecisionSignalKind.InformationalEvent
+                && p.Payload != null
+                && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                && et == eventType).ToList();
+
+        private static IReadOnlyDictionary<string, object> Data(FakeSignalIngressSink.PostedSignal posted) =>
+            (IReadOnlyDictionary<string, object>)posted.TypedPayload!;
+
+        private static OobeUpdateRegistrySnapshot.KeyState NdupKey(string line) =>
+            new OobeUpdateRegistrySnapshot.KeyState("setupOobeNdup", @"SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OOBE\NDUP",
+                exists: true, hasValues: true, line: line);
+
+        // ------------------------------------------------------------- breadcrumbs ----
+
+        [Fact]
+        public void PageStart_NamesTheCxid()
+        {
+            Assert.Equal("CXH page started: OobeNDUP",
+                ShellCoreTracker.FormatCxhBreadcrumb(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, lastPage: null));
+        }
+
+        [Fact]
+        public void PageStop_IsAttributedToTheLastStartedPage()
+        {
+            // 62405 names no page — it ends the one started last.
+            Assert.Equal("CXH page stopped: OobeNDUP (result=success)",
+                ShellCoreTracker.FormatCxhBreadcrumb(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, lastPage: "OobeNDUP"));
+            Assert.Equal("CXH page stopped: ? (result=success)",
+                ShellCoreTracker.FormatCxhBreadcrumb(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, lastPage: null));
+        }
+
+        [Fact]
+        public void UpdatePageEventNames_AreLogged_FromBothEventIds()
+        {
+            Assert.Equal("CXH event: ExpeditedUpdate_startWUScanStarted",
+                ShellCoreTracker.FormatCxhBreadcrumb(ShellCoreTracker.EventId_ShellCore_WebAppEventName, ScanStartedName, lastPage: null));
+            Assert.Equal("CXH event: ExpeditedUpdate_commitExpeditionDownloadInstallAsyncSucceeded",
+                ShellCoreTracker.FormatCxhBreadcrumb(ShellCoreTracker.EventId_ShellCore_WebAppEvent, DownloadSucceededWithValue, lastPage: null));
+        }
+
+        [Fact]
+        public void UnsafeEventValues_NeverReachTheLog()
+        {
+            var crumb = ShellCoreTracker.FormatCxhBreadcrumb(
+                ShellCoreTracker.EventId_ShellCore_WebAppEvent, DownloadSucceededWithValue, lastPage: null);
+
+            Assert.NotNull(crumb);
+            Assert.DoesNotContain("microsoftonline", crumb);
+            Assert.DoesNotContain("url", crumb!, StringComparison.OrdinalIgnoreCase);
+        }
+
+        [Fact]
+        public void SafeEventValues_AreLogged()
+        {
+            Assert.Equal("CXH event: ExpeditedUpdate_isNDUPAllowedByCSPSucceeded (value=true)",
+                ShellCoreTracker.FormatCxhBreadcrumb(ShellCoreTracker.EventId_ShellCore_WebAppEvent, CspGateTrue, lastPage: null));
+        }
+
+        [Fact]
+        public void OtherEventNames_AreNotLogged()
+        {
+            // Ordinary page traffic (Navigate, Visible, ESP progress) stays out of the log.
+            Assert.Null(ShellCoreTracker.FormatCxhBreadcrumb(
+                ShellCoreTracker.EventId_ShellCore_WebAppEvent, NavigateWithTenantUrl, lastPage: "OobeNDUP"));
+            Assert.Null(ShellCoreTracker.FormatCxhBreadcrumb(
+                ShellCoreTracker.EventId_ShellCore_WebAppEvent, "CommercialOOBE_ESPProgress_Page_Exiting", lastPage: null));
+        }
+
+        [Theory]
+        [InlineData("")]
+        [InlineData("CloudExperienceHost Web App Activity started.")]
+        public void PageStartWithoutCxid_IsNoBreadcrumb(string description)
+        {
+            Assert.Null(ShellCoreTracker.FormatCxhBreadcrumb(ShellCoreTracker.EventId_ShellCore_WebAppStarted, description, lastPage: null));
+        }
+
+        [Fact]
+        public void LongTokens_AreBounded()
+        {
+            var longCxid = new string('X', 500);
+            var crumb = ShellCoreTracker.FormatCxhBreadcrumb(
+                ShellCoreTracker.EventId_ShellCore_WebAppStarted, $"CloudExperienceHost Web App Activity started. CXID: '{longCxid}'.", lastPage: null);
+
+            Assert.NotNull(crumb);
+            Assert.True(crumb!.Length < 200, crumb);
+            Assert.EndsWith("…", crumb);
+        }
+
+        [Theory]
+        [InlineData("OobeNDUP", true)]
+        [InlineData("RebootNDUP", true)]
+        [InlineData("EarlyRebootNDUP", true)]
+        [InlineData("ExpeditedUpdate_startWUScanStarted", true)]
+        [InlineData("AADHello", false)]
+        [InlineData("MDMProgressAfterAADRefactored", false)]
+        [InlineData(null, false)]
+        public void UpdatePageTokens_AreRecognized(string? token, bool expected)
+        {
+            Assert.Equal(expected, ShellCoreTracker.IsUpdatePageToken(token!));
+        }
+
+        // ------------------------------------------------------ update page records ----
+
+        [Fact]
+        public void UpdatePageRecords_ArePageStartsStopsAndNames_OfTheUpdatePageOnly()
+        {
+            var start = ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, lastPage: null);
+            Assert.Equal(OobeUpdatePageRecord.PageStarted, start!.CxhEvent);
+            Assert.Equal("OobeNDUP", start.Page);
+
+            var stop = ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, lastPage: "RebootNDUP");
+            Assert.Equal(OobeUpdatePageRecord.PageStopped, stop!.CxhEvent);
+            Assert.Equal("RebootNDUP", stop.Page);
+            Assert.Equal("success", stop.Result);
+
+            var name = ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppEventName, ScanStartedName, lastPage: null);
+            Assert.Equal(OobeUpdatePageRecord.EventName, name!.CxhEvent);
+            Assert.Equal("ExpeditedUpdate_startWUScanStarted", name.Name);
+            Assert.Null(name.Value);
+
+            // Other pages and names are no update-page records.
+            Assert.Null(ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppStarted, EspPageStarted, lastPage: null));
+            Assert.Null(ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, lastPage: "MDMProgressAfterAADRefactored"));
+            Assert.Null(ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppEvent, NavigateWithTenantUrl, lastPage: "OobeNDUP"));
+        }
+
+        [Fact]
+        public void UpdatePageRecord_CarriesOnlyASafeValue()
+        {
+            var unsafeValue = ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppEvent, DownloadSucceededWithValue, lastPage: null);
+            Assert.Null(unsafeValue!.Value);
+
+            var gate = ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppEvent, CspGateTrue, lastPage: null);
+            Assert.Equal("true", gate!.Value);
+        }
+
+        [Theory]
+        [InlineData("true", "true")]
+        [InlineData("FALSE", "FALSE")]
+        [InlineData("0", "0")]
+        [InlineData("-2147024891", "-2147024891")]
+        [InlineData("0x80240022", "0x80240022")]
+        [InlineData("12345678901", null)]          // more than ten digits
+        [InlineData("0x123456789", null)]          // more than eight hex digits
+        [InlineData("https://login.microsoftonline.com/x", null)]
+        [InlineData("{\"result\":0}", null)]
+        [InlineData("true and more", null)]
+        [InlineData("", null)]
+        public void SafeValues_AreBooleansIntegersAndHresults(string value, string? expected)
+        {
+            var description = $"CloudExperienceHost Web App Event 2. Name: 'ExpeditedUpdate_x', Value: '{value}'.";
+
+            Assert.Equal(expected, ShellCoreTracker.ExtractSafeValue(description));
+        }
+
+        [Fact]
+        public void LiveUpdatePage_IsReported_WithTheRegistryState_AndRaisesNothing()
+        {
+            _registry = new[] { NdupKey("EnableExpeditedUpdate=1") };
+            using var tracker = Build();
+            var raised = 0;
+            tracker.EspExited += (_, _) => raised++;
+            tracker.EspFailureDetected += (_, _) => raised++;
+            tracker.FinalizingSetupPhaseTriggered += (_, _) => raised++;
+
+            tracker.ProcessEvent(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, "Microsoft-Windows-Shell-Core", isBackfill: false);
+            tracker.ProcessEvent(ShellCoreTracker.EventId_ShellCore_WebAppEventName, ScanStartedName, At.AddMinutes(1), "Microsoft-Windows-Shell-Core", isBackfill: false);
+            _registry = new[] { NdupKey("EnableExpeditedUpdate=1, EnableExpeditedUpdateSyncInstallCompleted=1") };
+            tracker.ProcessEvent(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(30), "Microsoft-Windows-Shell-Core", isBackfill: false);
+
+            var pages = ByType(Constants.EventTypes.OobeUpdatePage);
+            Assert.Equal(new object[] { "page_started", "event_name", "page_stopped" }, pages.Select(p => Data(p)["cxhEvent"]).ToArray());
+            Assert.All(pages, p => Assert.Equal(false, Data(p)["backfill"]));
+
+            var states = ByType(Constants.EventTypes.OobeUpdateState);
+            Assert.Equal(new object[] { "update_page_started", "update_page_stopped" }, states.Select(s => Data(s)["moment"]).ToArray());
+            Assert.All(states, s => Assert.Equal("OobeNDUP", Data(s)["page"]));
+
+            // Telemetry only — no ESP signal, no other event.
+            Assert.Equal(0, raised);
+            Assert.False(tracker.IsEspExitedForTest);
+            Assert.Equal(pages.Count + states.Count, _sink.Posted.Count);
+        }
+
+        [Fact]
+        public void OtherPages_AreNotReported()
+        {
+            _registry = new[] { NdupKey("EnableExpeditedUpdate=1") };
+            using var tracker = Build();
+
+            tracker.ProcessEvent(ShellCoreTracker.EventId_ShellCore_WebAppStarted, EspPageStarted, At, "Microsoft-Windows-Shell-Core", isBackfill: false);
+            tracker.ProcessEvent(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(1), "Microsoft-Windows-Shell-Core", isBackfill: false);
+
+            Assert.Empty(_sink.Posted);
+        }
+
+        [Fact]
+        public void Backfill_ReportsTheUpdatePage_WithItsEventTimes_ButReadsNoRegistry()
+        {
+            // The registry shows the state now, not at the record's time.
+            var reads = 0;
+            using var tracker = new ShellCoreTracker("S1", "T1",
+                new InformationalEventPost(_sink, new VirtualClock(At)),
+                new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                helloTracker: null,
+                oobeUpdateRegistryReader: () => { reads++; return new[] { NdupKey("EnableExpeditedUpdate=1") }; });
+
+            tracker.ReplayBackfillRecords(new[]
+            {
+                (ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At.AddMinutes(-4)),
+                (ShellCoreTracker.EventId_ShellCore_WebAppEventName, ScanStartedName, At.AddMinutes(-3)),
+                (ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(-2)),
+            });
+
+            var pages = ByType(Constants.EventTypes.OobeUpdatePage);
+            Assert.Equal(3, pages.Count);
+            Assert.All(pages, p => Assert.Equal(true, Data(p)["backfill"]));
+            Assert.Equal(At.AddMinutes(-4), pages[0].OccurredAtUtc);
+            Assert.Equal(0, reads);
+            // Nothing else: no ESP exit or failure was in the window, so no skipped-records trace.
+            Assert.Equal(3, _sink.Posted.Count);
+        }
+
+        // ------------------------------------------------------------ localization ----
+
+        [Fact]
+        public void LocalizedRecords_AreReadFromTheirProperties()
+        {
+            using var tracker = Build();
+
+            tracker.ProcessEvent(ShellCoreTracker.EventId_ShellCore_WebAppStarted, FrenchNdupStarted, At, "Microsoft-Windows-Shell-Core",
+                isBackfill: false, properties: new[] { "OobeNDUP" });
+            tracker.ProcessEvent(ShellCoreTracker.EventId_ShellCore_WebAppEvent, FrenchCspGate, At.AddSeconds(5), "Microsoft-Windows-Shell-Core",
+                isBackfill: false, properties: new[] { "ExpeditedUpdate_isNDUPAllowedByCSPSucceeded", "true" });
+            tracker.ProcessEvent(ShellCoreTracker.EventId_ShellCore_WebAppStopped, FrenchPageStopped, At.AddMinutes(1), "Microsoft-Windows-Shell-Core",
+                isBackfill: false, properties: new[] { "success" });
+
+            var pages = ByType(Constants.EventTypes.OobeUpdatePage).Select(Data).ToList();
+            Assert.Equal(new object[] { "page_started", "event_name", "page_stopped" }, pages.Select(d => d["cxhEvent"]).ToArray());
+            Assert.Equal("OobeNDUP", pages[0]["page"]);
+            Assert.Equal("ExpeditedUpdate_isNDUPAllowedByCSPSucceeded", pages[1]["name"]);
+            Assert.Equal("true", pages[1]["value"]);
+            Assert.Equal("OobeNDUP", pages[2]["page"]);
+            Assert.Equal("success", pages[2]["result"]);
+        }
+
+        [Fact]
+        public void LocalizedMessage_WithoutProperties_DoesNotYieldItsLabelledFields()
+        {
+            // Why the properties are read: the French labels are not the manifest's.
+            Assert.Null(ShellCoreTracker.ReadCxhFields(ShellCoreTracker.EventId_ShellCore_WebAppStopped, FrenchPageStopped, properties: null).Primary);
+            Assert.Null(ShellCoreTracker.ReadCxhFields(ShellCoreTracker.EventId_ShellCore_WebAppEvent, FrenchCspGate, properties: null).Primary);
+
+            Assert.Equal("success",
+                ShellCoreTracker.ReadCxhFields(ShellCoreTracker.EventId_ShellCore_WebAppStopped, FrenchPageStopped, new[] { "success" }).Primary);
+        }
+
+        [Theory]
+        [InlineData("CloudExperienceHost Web App Event 2. Name: 'ExpeditedUpdate_x', Value: 'true'.")]
+        [InlineData("CloudExperienceHost Web App Event 2. Name : « ExpeditedUpdate_x », Value : « true ».")]
+        [InlineData("CloudExperienceHost Web App Event 2. Name\u00A0: «\u202FExpeditedUpdate_x\u202F», Value\u00A0: «\u00A0true\u00A0».")]
+        public void MessageFallback_AcceptsQuotesAndGuillemets(string description)
+        {
+            var fields = ShellCoreTracker.ReadCxhFields(ShellCoreTracker.EventId_ShellCore_WebAppEvent, description, properties: null);
+
+            Assert.Equal("ExpeditedUpdate_x", fields.Primary);
+            Assert.Equal("true", fields.Value);
+        }
+
+        [Fact]
+        public void PropertyValue_LeavesTheTrackerOnlyInASafeForm()
+        {
+            var fields = ShellCoreTracker.ReadCxhFields(ShellCoreTracker.EventId_ShellCore_WebAppEvent, "",
+                new[] { "ExpeditedUpdate_commitExpeditionDownloadInstallAsyncSucceeded", "{\"url\":\"https://login.microsoftonline.com/x\"}" });
+
+            var record = ShellCoreTracker.ParseUpdatePageRecord(ShellCoreTracker.EventId_ShellCore_WebAppEvent, fields, lastPage: null);
+            Assert.Equal("ExpeditedUpdate_commitExpeditionDownloadInstallAsyncSucceeded", record!.Name);
+            Assert.Null(record.Value);
+            Assert.DoesNotContain("microsoftonline",
+                ShellCoreTracker.FormatCxhBreadcrumb(ShellCoreTracker.EventId_ShellCore_WebAppEvent, fields, lastPage: null));
+        }
+
+        // ------------------------------------------------------- restart watermark ----
+
+        [Fact]
+        public void RestartBackfill_SkipsUpdatePageRecords_AnEarlierRunReported()
+        {
+            using (var first = Build(StateDirectory))
+            {
+                Live(first, ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, recordId: 500);
+                Live(first, ShellCoreTracker.EventId_ShellCore_WebAppEventName, ScanStartedName, At.AddMinutes(1), recordId: 501);
+            }
+
+            // The restart reads the minutes before it again — plus the stop the first run missed.
+            using var second = Build(StateDirectory);
+            second.LoadPageWatermark();
+            second.ReplayBackfillRecords(new[]
+            {
+                new ShellCoreRecord(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, recordId: 500),
+                new ShellCoreRecord(ShellCoreTracker.EventId_ShellCore_WebAppEventName, ScanStartedName, At.AddMinutes(1), recordId: 501),
+                new ShellCoreRecord(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(2), recordId: 502),
+            });
+
+            var pages = ByType(Constants.EventTypes.OobeUpdatePage).Select(Data).ToList();
+            Assert.Equal(new object[] { "page_started", "event_name", "page_stopped" }, pages.Select(d => d["cxhEvent"]).ToArray());
+            Assert.Equal(new object[] { false, false, true }, pages.Select(d => d["backfill"]).ToArray());
+            // The skipped start still names the page the stop belongs to.
+            Assert.Equal("OobeNDUP", pages[2]["page"]);
+        }
+
+        [Fact]
+        public void SameRecord_FromTheLiveWatcherAndTheBackfill_IsReportedOnce()
+        {
+            // The live watcher is armed before the backfill runs, so both can deliver a record.
+            using var tracker = Build(StateDirectory);
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, recordId: 700);
+            tracker.ReplayBackfillRecords(new[]
+            {
+                new ShellCoreRecord(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, recordId: 700),
+            });
+
+            Assert.Single(ByType(Constants.EventTypes.OobeUpdatePage));
+        }
+
+        [Fact]
+        public void Watermark_FollowsReportedRecordsOnly()
+        {
+            using var tracker = Build(StateDirectory);
+            for (var i = 0; i <= OobeUpdateTelemetry.MaxPageEventsPerKey; i++)
+                Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppEventName, ScanStartedName, At.AddSeconds(i), recordId: 800 + i);
+
+            // The repeat over the per-name cap is claimed for this run, not written down.
+            Assert.Equal(OobeUpdateTelemetry.MaxPageEventsPerKey, ByType(Constants.EventTypes.OobeUpdatePage).Count);
+            var state = JsonConvert.DeserializeObject<EventRecordWatermark.WatermarkState>(
+                File.ReadAllText(Path.Combine(StateDirectory, ShellCoreTracker.PageWatermarkStateFileName)));
+            Assert.Equal(800 + OobeUpdateTelemetry.MaxPageEventsPerKey - 1, state!.LastRecordId);
+        }
+
+        [Fact]
+        public void RecordsWithoutARecordId_AreNotDeduplicated()
+        {
+            using var tracker = Build(StateDirectory);
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, recordId: -1);
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At.AddMinutes(5), recordId: -1);
+
+            Assert.Equal(2, ByType(Constants.EventTypes.OobeUpdatePage).Count);
+            Assert.False(File.Exists(Path.Combine(StateDirectory, ShellCoreTracker.PageWatermarkStateFileName)));
+        }
+
+        [Fact]
+        public void AgentStartAndStop_ReportTheRegistryState_StopOnce()
+        {
+            _registry = new[] { NdupKey("EnableExpeditedUpdate=1") };
+            var tracker = Build();
+
+            tracker.Start();
+            _registry = new[] { NdupKey("EnableExpeditedUpdate=1, ExpeditedUpdateStatus=2") };
+            tracker.Stop();
+            tracker.Stop();
+            tracker.Dispose();
+
+            var states = ByType(Constants.EventTypes.OobeUpdateState);
+            Assert.Equal(new object[] { "agent_start", "agent_stop" }, states.Select(s => Data(s)["moment"]).ToArray());
+        }
+
+        [Fact]
+        public void TrackerThatNeverStarted_ReportsNothingAtStop()
+        {
+            _registry = new[] { NdupKey("EnableExpeditedUpdate=1") };
+            var tracker = Build();
+
+            tracker.Dispose();
+
+            Assert.Empty(_sink.Posted);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/ShellCoreTrackerHelloWizardTests.cs

@@ -84,6 +84,55 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring
             Assert.False(raised);
         }
 
+        [Fact]
+        public void ProcessEvent_62404_NGC_in_a_localized_message_is_read_from_the_cxid_property()
+        {
+            // A French Windows quotes the CXID in guillemets — the "'NGC'" substring never matched.
+            using var tmp = new TempDirectory();
+            using var tracker = MakeTracker(tmp, new VirtualClock(ClockNow));
+            var raised = 0;
+            tracker.HelloWizardStarted += (_, _) => raised++;
+
+            tracker.ProcessEvent(
+                eventId: ShellCoreTracker.EventId_ShellCore_WebAppStarted,
+                description: "Activité d’application web CloudExperienceHost démarrée. CXID : « NGC ».",
+                timestamp: ClockNow,
+                providerName: "Microsoft-Windows-Shell-Core",
+                isBackfill: false,
+                properties: new[] { "NGC" });
+
+            Assert.Equal(1, raised);
+        }
+
+        [Theory]
+        [InlineData("AADHello", true)]
+        [InlineData("NGC", true)]
+        [InlineData("NGCPin", false)]
+        [InlineData("OobeNDUP", false)]
+        public void HelloWizardStart_is_decided_by_the_cxid(string cxid, bool expected)
+        {
+            Assert.Equal(expected, ShellCoreTracker.IsHelloWizardStart(cxid, description: "CXID: 'AADHello'"));
+        }
+
+        [Fact]
+        public void Backfill_62404_reads_the_cxid_property()
+        {
+            using var tmp = new TempDirectory();
+            using var tracker = MakeTracker(tmp, new VirtualClock(ClockNow));
+            var captured = new List<HelloWizardStartedEventArgs>();
+            tracker.HelloWizardStarted += (_, args) => captured.Add(args);
+
+            var historical = ClockNow.AddMinutes(-3);
+            tracker.ReplayBackfillRecords(new[]
+            {
+                new ShellCoreRecord(ShellCoreTracker.EventId_ShellCore_WebAppStarted,
+                    "Activité d’application web CloudExperienceHost démarrée. CXID : « NGC ».", historical,
+                    recordId: 42, properties: new[] { "NGC" }),
+            });
+
+            Assert.Equal(historical, Assert.Single(captured).OccurredAtUtc);
+        }
+
         [Fact]
         public void Backfill_62404_raises_once_with_historical_timestamp()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/ShellCoreTrackerUpdatePageBackfillTests.cs

@@ -0,0 +1,225 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.Shared;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring
+{
+    /// <summary>
+    /// The first run's update page backfill (<see cref="ShellCoreTracker.BackfillUpdatePageTelemetry"/>)
+    /// and the page a stop belongs to across backfill and live records. The first run has no
+    /// replay — its backfill is telemetry and nothing else, so a Hello-wizard start, an ESP exit
+    /// or an ESP failure in the window must not leave the tracker on any rail.
+    /// </summary>
+    public sealed class ShellCoreTrackerUpdatePageBackfillTests : IDisposable
+    {
+        private static readonly DateTime At = new DateTime(2026, 10, 5, 13, 10, 0, DateTimeKind.Utc);
+
+        private const string NdupStarted = "CloudExperienceHost Web App Activity started. CXID: 'OobeNDUP'.";
+        private const string RebootNdupStarted = "CloudExperienceHost Web App Activity started. CXID: 'RebootNDUP'.";
+        private const string AadHelloStarted = "CloudExperienceHost Web App Activity started. CXID: 'AADHello'.";
+        private const string PageStopped = "CloudExperienceHost Web App Activity stopped. Result: 'success'.";
+        private const string DownloadSucceeded =
+            "CloudExperienceHost Web App Event 1. Name: 'SdxWebAppCloudNDUP_processStatusChangeFromHandler_downloadSucceeded'.";
+        private const string EspExit = "CommercialOOBE_ESPProgress_Page_Exiting";
+        private const string EspFailure = "CommercialOOBE_ESPProgress_Failure";
+        private const string WhiteGloveSuccess = "CommercialOOBE_ESPProgress_WhiteGlove_Success";
+
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly FakeSignalIngressSink _sink = new FakeSignalIngressSink();
+        private int _registryReads;
+
+        public void Dispose() => _tmp.Dispose();
+
+        private ShellCoreTracker Build() =>
+            new ShellCoreTracker("S1", "T1",
+                new InformationalEventPost(_sink, new VirtualClock(At)),
+                new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                helloTracker: null,
+                oobeUpdateRegistryReader: () => { _registryReads++; return Array.Empty<OobeUpdateRegistrySnapshot.KeyState>(); },
+                stateDirectory: Path.Combine(_tmp.Path, "state"));
+
+        private static void Live(ShellCoreTracker tracker, int eventId, string description, DateTime at, long recordId) =>
+            tracker.ProcessEvent(eventId, description, at, "Microsoft-Windows-Shell-Core", isBackfill: false, recordId: recordId);
+
+        private static ShellCoreRecord Record(int eventId, string description, DateTime at, long recordId) =>
+            new ShellCoreRecord(eventId, description, at, recordId);
+
+        private IReadOnlyList<IReadOnlyDictionary<string, object>> Pages() =>
+            _sink.Posted
+                .Where(p => p.Kind == DecisionSignalKind.InformationalEvent
+                    && p.Payload != null
+                    && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                    && et == Constants.EventTypes.OobeUpdatePage)
+                .Select(p => (IReadOnlyDictionary<string, object>)p.TypedPayload!)
+                .ToList();
+
+        // ------------------------------------------------------------ first run ----
+
+        [Fact]
+        public void FirstRunBackfill_ReportsTheUpdatePage_AndNothingElse()
+        {
+            using var tracker = Build();
+            var raised = new List<string>();
+            tracker.HelloWizardStarted += (_, _) => raised.Add("hello");
+            tracker.FinalizingSetupPhaseTriggered += (_, reason) => raised.Add($"finalizing:{reason}");
+            tracker.EspExited += (_, _) => raised.Add("exit");
+            tracker.EspFailureDetected += (_, _) => raised.Add("failure");
+            tracker.WhiteGloveCompleted += (_, _) => raised.Add("whiteglove");
+
+            tracker.ReplayUpdatePageTelemetry(new[]
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspExit, At.AddMinutes(-41), 95),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspFailure, At.AddSeconds(-2430), 96),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, WhiteGloveSuccess, At.AddSeconds(-2420), 97),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At.AddMinutes(-40), 100),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEventName, DownloadSucceeded, At.AddMinutes(-30), 101),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, AadHelloStarted, At.AddMinutes(-2), 110),
+            });
+
+            Assert.Empty(raised);
+            Assert.False(tracker.IsEspExitedForTest);
+            Assert.False(tracker.IsWhiteGloveDetectedForTest);
+            var pages = Pages();
+            Assert.Equal(new object[] { "page_started", "event_name" }, pages.Select(d => d["cxhEvent"]).ToArray());
+            Assert.All(pages, d => Assert.Equal(true, d["backfill"]));
+            // No agent_trace, no ESP or Hello event — only the two page rows.
+            Assert.Equal(2, _sink.Posted.Count);
+            // The registry shows the state now, not at the records' time.
+            Assert.Equal(0, _registryReads);
+        }
+
+        [Fact]
+        public void FirstRunBackfill_KeepsTheEventTimes()
+        {
+            using var tracker = Build();
+
+            tracker.ReplayUpdatePageTelemetry(new[]
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At.AddMinutes(-40), 100),
+            });
+
+            var posted = Assert.Single(_sink.Posted);
+            Assert.Equal(At.AddMinutes(-40), posted.OccurredAtUtc);
+        }
+
+        [Fact]
+        public void LiveStop_FindsThePageThatStartedBeforeTheAgent()
+        {
+            using var tracker = Build();
+            tracker.ReplayUpdatePageTelemetry(new[]
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At.AddMinutes(-40), 100),
+            });
+
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(5), 120);
+
+            var stop = Pages().Last();
+            Assert.Equal("page_stopped", stop["cxhEvent"]);
+            Assert.Equal("OobeNDUP", stop["page"]);
+            Assert.Equal(false, stop["backfill"]);
+        }
+
+        [Fact]
+        public void SameRecord_FromTheLiveWatcherAndTheFirstRunBackfill_IsReportedOnce()
+        {
+            // The live watcher is armed before the backfill reads, so both can deliver a record.
+            using var tracker = Build();
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, 700);
+            tracker.ReplayUpdatePageTelemetry(new[]
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, 700),
+            });
+
+            Assert.Single(Pages(), d => (string)d["cxhEvent"] == "page_started");
+        }
+
+        // ---------------------------------------------------- the page of a stop ----
+
+        [Fact]
+        public void ReplayedOlderStart_DoesNotTakeOverTheNextLiveStop()
+        {
+            // A restart replay reads records older than the live watcher's; before, its page start
+            // overwrote the live page and the next live stop was attributed to the old page.
+            using var tracker = Build();
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStarted, RebootNdupStarted, At, 900);
+            tracker.ReplayBackfillRecords(new[]
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At.AddMinutes(-20), 850),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEventName, DownloadSucceeded, At.AddMinutes(-19), 851),
+            });
+
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(1), 901);
+
+            var stop = Pages().Last();
+            Assert.Equal("page_stopped", stop["cxhEvent"]);
+            Assert.Equal("RebootNDUP", stop["page"]);
+        }
+
+        [Fact]
+        public void BackfilledStop_BelongsToTheStartOfItsOwnBatch()
+        {
+            using var tracker = Build();
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStarted, RebootNdupStarted, At, 900);
+
+            tracker.ReplayUpdatePageTelemetry(new[]
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At.AddMinutes(-20), 850),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(-18), 852),
+            });
+
+            var stop = Pages().Last();
+            Assert.Equal("page_stopped", stop["cxhEvent"]);
+            Assert.Equal("OobeNDUP", stop["page"]);
+            Assert.Equal(true, stop["backfill"]);
+        }
+
+        [Fact]
+        public void BackfilledStopWithoutItsStart_IsNotGivenTheLivePage()
+        {
+            using var tracker = Build();
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, 900);
+
+            tracker.ReplayUpdatePageTelemetry(new[]
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(-18), 852),
+            });
+
+            Assert.DoesNotContain(Pages(), d => (string)d["cxhEvent"] == "page_stopped");
+        }
+
+        [Fact]
+        public void NewerBackfilledStart_MovesTheLivePageForward()
+        {
+            // Records written between arming the watcher and the backfill's read are newer than
+            // the last live start the watcher delivered before them.
+            using var tracker = Build();
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStarted, NdupStarted, At, 900);
+            tracker.ReplayUpdatePageTelemetry(new[]
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, RebootNdupStarted, At.AddSeconds(30), 905),
+            });
+
+            Live(tracker, ShellCoreTracker.EventId_ShellCore_WebAppStopped, PageStopped, At.AddMinutes(1), 906);
+
+            Assert.Equal("RebootNDUP", Pages().Last()["page"]);
+        }
+
+        [Fact]
+        public void UpdatePageLookback_IsInsideTheReplayClamp()
+        {
+            Assert.Equal(ShellCoreTracker.UpdatePageBackfillLookbackMinutes,
+                ShellCoreTracker.ClampLookbackMinutes(ShellCoreTracker.UpdatePageBackfillLookbackMinutes));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/ImeRegistryAppStateObserverTests.cs

@@ -61,7 +61,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
 
         // IME AppInstallStatus values (StatusServiceReports\..\Status), stable IME 1.50 .. 1.106.
         // 1001/1003 sit inside the 1000 band but are NOT terminal — IME maps every InProgress
-        // enforcement state to 1001 (verified in the decompiled 1.106 StatusServiceHelpers).
+        // enforcement state to 1001 (verified against IME 1.106).
         [Theory]
         [InlineData(1000, "installed")]
         [InlineData(1002, "installed")]

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/ImeRegistryScriptResultObserverTests.cs

@@ -0,0 +1,411 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using Xunit;
+using SharedEventTypes = AutopilotMonitor.Shared.Constants.EventTypes;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
+{
+    /// <summary>
+    /// D-316: IME saves every platform script's result under Policies\&lt;user&gt;\&lt;policy&gt; after reporting the
+    /// batch; the observer checks the tracker's emitted run against it. The field case (session 756970cf): the run
+    /// had been given a Win32 detection script's end block — exit 1 and "Detection Started" output — while IME saved
+    /// the bootstrap output of the platform script itself.
+    /// </summary>
+    public sealed class ImeRegistryScriptResultObserverTests
+    {
+        private const string DeviceUser = "00000000-0000-0000-0000-000000000000";
+        private const string PolicyA = "1d6f0a52-3c4e-4b7a-9e21-5f8c7d2b9a10";
+        private const string PolicyB = "2b7d9e41-8c3a-4f60-a5d2-9e1b7c4f3a08";
+        private const string OwnStdout = "=== bootstrap loader started ===\nInstaller finished (exit code 0).";
+        private const string ForeignStdout = "VERBOSE: === Sample Suite Detection Started ===\nWARNING: === DETECTION FAILED ===";
+        private static readonly DateTime T0 = new DateTime(2026, 10, 3, 20, 59, 0, DateTimeKind.Utc);
+
+        // ── PlatformOutputJudge ─────────────────────────────────────────────────
+
+        private static PlatformScriptRun Run(string? stdout, string? stderr = null, int? exitCode = 0, string result = "Success", string resultSource = "ime_policy_result")
+            => new PlatformScriptRun { PolicyId = PolicyA, UserId = DeviceUser, RunId = "run-1", Emitted = true, Result = result, ResultSource = resultSource, ExitCode = exitCode, Stdout = stdout, Stderr = stderr };
+
+        private static string Details(string executionMessage)
+            => "{\"Version\":1,\"SigningCode\":15,\"EncryptionCode\":19,\"ExecutionMsg\":" + System.Text.Json.JsonSerializer.Serialize(executionMessage) + "}";
+
+        private static SavedScriptResult Saved(string? executionMessage, string result = "Success", int errorCode = 0, string user = DeviceUser, string policy = PolicyA, string stamp = "10/3/2026 9:00:00 PM")
+            => new SavedScriptResult
+            {
+                UserId = user,
+                PolicyId = policy,
+                Result = result,
+                ErrorCode = errorCode,
+                ResultDetails = executionMessage == null ? null : Details(executionMessage),
+                LastUpdatedTimeUtc = stamp,
+            };
+
+        [Fact]
+        public void Field_case_detection_output_on_the_platform_run_is_foreign_and_the_saved_stdout_replaces_it()
+        {
+            var judgement = PlatformOutputJudge.Judge(Run(ForeignStdout, string.Empty, exitCode: 1), Saved(OwnStdout.Replace("\n", "\r\n")));
+            Assert.Equal(PlatformOutputVerdict.Foreign, judgement.Verdict);
+            Assert.Equal("stdout_differs", judgement.Reason);
+            Assert.Equal(OwnStdout, judgement.Stdout);
+            Assert.Equal(string.Empty, judgement.Stderr);
+        }
+
+        [Fact]
+        public void Matching_output_is_verified_across_line_ending_and_trim_differences()
+        {
+            var judgement = PlatformOutputJudge.Judge(Run(OwnStdout, string.Empty), Saved("  " + OwnStdout.Replace("\n", "\r\n") + "\r\n"));
+            Assert.Equal(PlatformOutputVerdict.Verified, judgement.Verdict);
+        }
+
+        [Fact]
+        public void Output_cut_by_the_tracker_is_verified_against_the_longer_saved_text()
+        {
+            var full = string.Concat(Enumerable.Repeat("line of output\n", 1000)).TrimEnd();
+            var emitted = ImeLogTracker.TruncateOutput(full);
+            Assert.EndsWith(ImeLogTracker.OutputTruncationMarker, emitted);
+            Assert.Equal(PlatformOutputVerdict.Verified, PlatformOutputJudge.Judge(Run(emitted), Saved(full)).Verdict);
+        }
+
+        [Fact]
+        public void Both_empty_is_verified_but_stderr_on_a_success_is_another_executors()
+        {
+            Assert.Equal(PlatformOutputVerdict.Verified, PlatformOutputJudge.Judge(Run(string.Empty), Saved(string.Empty)).Verdict);
+            var judgement = PlatformOutputJudge.Judge(Run(string.Empty, "Get-Item : not found"), Saved(string.Empty));
+            Assert.Equal(PlatformOutputVerdict.Foreign, judgement.Verdict);
+            Assert.Equal("stderr_on_success", judgement.Reason);
+        }
+
+        [Fact]
+        public void Explicitly_empty_emitted_output_against_saved_text_is_foreign()
+        {
+            Assert.Equal(PlatformOutputVerdict.Foreign, PlatformOutputJudge.Judge(Run(string.Empty), Saved(OwnStdout)).Verdict);
+            Assert.Equal(PlatformOutputVerdict.Foreign, PlatformOutputJudge.Judge(Run(OwnStdout), Saved(string.Empty)).Verdict);
+        }
+
+        [Fact]
+        public void Output_never_read_is_completed_from_the_saved_text_and_the_exit_code_stands()
+        {
+            var judgement = PlatformOutputJudge.Judge(Run(null), Saved(OwnStdout));
+            Assert.Equal(PlatformOutputVerdict.Repaired, judgement.Verdict);
+            Assert.Equal("stdout_missing", judgement.Reason);
+            Assert.Equal(OwnStdout, judgement.Stdout);
+            Assert.Equal(PlatformOutputVerdict.NotComparable, PlatformOutputJudge.Judge(Run(null), Saved(string.Empty)).Verdict);
+        }
+
+        [Fact]
+        public void Stdout_containing_the_output_error_separator_is_repaired_not_foreign()
+        {
+            // "write output done. output = X, error = " with X = "Copying files, error = 0 errors\nDone": the
+            // lazy split leaves "Copying files" as stdout and the rest as stderr.
+            var judgement = PlatformOutputJudge.Judge(
+                Run("Copying files", "0 errors\nDone, error ="),
+                Saved("Copying files, error = 0 errors\r\nDone"));
+            Assert.Equal(PlatformOutputVerdict.Repaired, judgement.Verdict);
+            Assert.Equal("stdout_split", judgement.Reason);
+            Assert.Equal("Copying files, error = 0 errors\nDone", judgement.Stdout);
+            Assert.Equal(string.Empty, judgement.Stderr);
+        }
+
+        [Fact]
+        public void A_prefix_without_the_split_explanation_is_foreign()
+        {
+            Assert.Equal(PlatformOutputVerdict.Foreign, PlatformOutputJudge.Judge(Run("Detected"), Saved("Detected and repaired")).Verdict);
+        }
+
+        [Fact]
+        public void Failed_with_stderr_is_judged_on_stderr()
+        {
+            Assert.Equal(PlatformOutputVerdict.Verified,
+                PlatformOutputJudge.Judge(Run("partial", "Access denied", 1, "Failed"), Saved("Access denied\r\n", "Failed", 99)).Verdict);
+
+            var missing = PlatformOutputJudge.Judge(Run(null, null, 1, "Failed"), Saved("Access denied", "Failed", 99));
+            Assert.Equal(PlatformOutputVerdict.Repaired, missing.Verdict);
+            Assert.Null(missing.Stdout);
+            Assert.Equal("Access denied", missing.Stderr);
+
+            var foreign = PlatformOutputJudge.Judge(Run("Detected", string.Empty, 0, "Failed"), Saved("Access denied", "Failed", 99));
+            Assert.Equal(PlatformOutputVerdict.Foreign, foreign.Verdict);
+            Assert.Equal(string.Empty, foreign.Stdout);
+            Assert.Equal("Access denied", foreign.Stderr);
+        }
+
+        [Fact]
+        public void Results_without_saved_output_or_from_another_run_are_not_compared()
+        {
+            Assert.Equal("no_saved_output", PlatformOutputJudge.Judge(Run(OwnStdout, null, 1, "Failed"), Saved("1", "Failed", 1)).Reason);
+            var hashMismatch = new SavedScriptResult { UserId = DeviceUser, PolicyId = PolicyA, Result = "Failed", ErrorCode = 2, ResultDetails = "Hash mismatch" };
+            Assert.Equal("no_execution_message", PlatformOutputJudge.Judge(Run(OwnStdout, null, 1, "Failed"), hashMismatch).Reason);
+            Assert.Equal("result_differs", PlatformOutputJudge.Judge(Run(OwnStdout), Saved("Access denied", "Failed", 99)).Reason);
+            // A result derived from the exit code (fallback) is not IME's — the saved one is.
+            Assert.Equal(PlatformOutputVerdict.Verified,
+                PlatformOutputJudge.Judge(Run(OwnStdout, null, 1, "Failed", "agentexecutor_fallback"), Saved(OwnStdout)).Verdict);
+        }
+
+        // ── PlatformScriptRunRegister ───────────────────────────────────────────
+
+        private static ScriptExecutionState Emitted(string policyId, string? stdout, int? exitCode = 0, string? userId = DeviceUser, string runId = "run-1")
+            => new ScriptExecutionState { PolicyId = policyId, ScriptType = "platform", UserId = userId, RunId = runId, Result = "Success", ResultSource = "ime_policy_result", ExitCode = exitCode, Stdout = stdout };
+
+        [Fact]
+        public void A_save_is_paired_only_after_the_tracker_read_past_it_and_the_run_was_emitted()
+        {
+            var runs = new PlatformScriptRunRegister();
+            runs.NoteStarted(DeviceUser, PolicyA, T0);
+            var seen = T0.AddSeconds(30);
+
+            Assert.Equal(PlatformRunClaim.Wait, runs.TryClaim(DeviceUser, PolicyA, seen, out _));
+            runs.NotePassCompleted(seen.AddSeconds(1));
+            Assert.Equal(PlatformRunClaim.Wait, runs.TryClaim(DeviceUser, PolicyA, seen, out _)); // pass started too early
+            runs.NotePassCompleted(seen + PlatformScriptRunRegister.TrackerCatchUp);
+            Assert.Equal(PlatformRunClaim.Wait, runs.TryClaim(DeviceUser, PolicyA, seen, out _)); // run not emitted yet
+
+            runs.NoteEmitted(Emitted(PolicyA, OwnStdout), T0.AddSeconds(40));
+            Assert.Equal(PlatformRunClaim.Claimed, runs.TryClaim(DeviceUser, PolicyA, seen, out var run));
+            Assert.Equal("run-1", run!.RunId);
+            Assert.Equal(OwnStdout, run.Stdout);
+            Assert.Equal(PlatformRunClaim.None, runs.TryClaim(DeviceUser, PolicyA, seen, out _)); // never twice
+        }
+
+        [Fact]
+        public void A_new_start_replaces_the_latest_run_of_its_key_and_other_users_stay_apart()
+        {
+            var runs = new PlatformScriptRunRegister();
+            runs.NoteStarted(DeviceUser, PolicyA, T0);
+            runs.NoteEmitted(Emitted(PolicyA, "first run"), T0.AddSeconds(5));
+            runs.NoteStarted(DeviceUser, PolicyA, T0.AddMinutes(30));
+            runs.NoteEmitted(Emitted(PolicyA, "second run", runId: "run-2"), T0.AddMinutes(30).AddSeconds(5));
+            const string user = "6c3f8a20-1d5e-4b97-8f4a-0e2d6b9c7a13";
+            runs.NoteStarted(user, PolicyA, T0.AddMinutes(31));
+            runs.NotePassCompleted(T0.AddHours(1));
+
+            Assert.Equal(PlatformRunClaim.Claimed, runs.TryClaim(DeviceUser, PolicyA, T0.AddMinutes(31), out var run));
+            Assert.Equal("second run", run!.Stdout);
+            Assert.Equal(PlatformRunClaim.Wait, runs.TryClaim(user, PolicyA, T0.AddMinutes(32), out _));
+            Assert.Equal(PlatformRunClaim.None, runs.TryClaim(DeviceUser, PolicyB, T0.AddMinutes(32), out _));
+        }
+
+        [Fact]
+        public void A_run_without_a_readable_user_id_is_claimed_by_its_policy()
+        {
+            var runs = new PlatformScriptRunRegister();
+            runs.NoteStarted(null, PolicyA, T0);
+            runs.NoteEmitted(Emitted(PolicyA, OwnStdout, userId: null), T0.AddSeconds(5));
+            runs.NotePassCompleted(T0.AddMinutes(5));
+            Assert.Equal(PlatformRunClaim.Claimed, runs.TryClaim(DeviceUser, PolicyA, T0.AddMinutes(1), out _));
+        }
+
+        [Fact]
+        public void Register_keeps_the_newest_runs_and_its_counters_report_each_change_once()
+        {
+            var runs = new PlatformScriptRunRegister();
+            for (var i = 0; i <= PlatformScriptRunRegister.MaxRuns; i++)
+                runs.NoteStarted(DeviceUser, Guid.NewGuid().ToString("D"), T0.AddSeconds(i));
+            runs.NoteStarted(DeviceUser, PolicyA, T0.AddHours(1));
+            runs.NoteEmitted(Emitted(PolicyA, OwnStdout), T0.AddHours(1));
+            runs.NotePassCompleted(T0.AddHours(2));
+            Assert.Equal(PlatformRunClaim.Claimed, runs.TryClaim(DeviceUser, PolicyA, T0.AddHours(1), out _));
+
+            Assert.False(runs.ConsumeCountersChanged());
+            runs.CountVerified();
+            runs.CountCorrected();
+            Assert.True(runs.ConsumeCountersChanged());
+            Assert.False(runs.ConsumeCountersChanged());
+            Assert.Equal(1, runs.Verified);
+            runs.RestoreCounters(7, 3);
+            Assert.Equal(7, runs.Verified);
+            Assert.Equal(3, runs.Corrected);
+        }
+
+        // ── observer flow ───────────────────────────────────────────────────────
+
+        private sealed class Fixture
+        {
+            public readonly FakeSignalIngressSink Sink = new FakeSignalIngressSink();
+            public readonly VirtualClock Clock = new VirtualClock(T0);
+            public readonly PlatformScriptRunRegister Runs = new PlatformScriptRunRegister();
+            public Dictionary<string, SavedScriptResult> Registry = new Dictionary<string, SavedScriptResult>(StringComparer.OrdinalIgnoreCase);
+            public readonly ImeRegistryScriptResultObserver Observer;
+
+            public Fixture()
+            {
+                Observer = new ImeRegistryScriptResultObserver(Runs, new InformationalEventPost(Sink, Clock), null, Clock,
+                    () => new Dictionary<string, SavedScriptResult>(Registry, StringComparer.OrdinalIgnoreCase));
+            }
+
+            public void Save(SavedScriptResult saved) => Registry[ImeRegistryScriptResultObserver.KeyOf(saved.UserId, saved.PolicyId)] = saved;
+
+            /// <summary>The tracker emitted a run, then kept polling past the save.</summary>
+            public void EmitRun(string policyId, string? stdout, int? exitCode, string runId)
+            {
+                Runs.NoteStarted(DeviceUser, policyId, Clock.UtcNow);
+                Runs.NoteEmitted(Emitted(policyId, stdout, exitCode, runId: runId), Clock.UtcNow);
+            }
+
+            public void TrackerCaughtUp() => Runs.NotePassCompleted(Clock.UtcNow);
+
+            public IReadOnlyList<FakeSignalIngressSink.PostedSignal> Corrections()
+                => Sink.Posted.Where(p => p.Payload != null
+                    && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                    && et == SharedEventTypes.ScriptOutputReconciliation).ToList();
+        }
+
+        [Fact]
+        public void Field_case_end_to_end_the_save_corrects_the_run_with_a_warning_naming_it()
+        {
+            var f = new Fixture();
+            f.Save(Saved("an older run of another policy", policy: PolicyB, stamp: "10/2/2026 8:00:00 AM"));
+            f.Observer.Tick("baseline");
+
+            f.EmitRun(PolicyA, ForeignStdout, 1, "run-a");
+            f.Save(Saved(OwnStdout));
+            f.Clock.Advance(TimeSpan.FromSeconds(1));
+            f.Observer.Tick("registry_change");
+            Assert.Empty(f.Corrections()); // the tracker has not read past the save yet
+
+            f.Clock.Advance(PlatformScriptRunRegister.TrackerCatchUp);
+            f.TrackerCaughtUp();
+            f.Observer.Tick("periodic");
+
+            var correction = Assert.Single(f.Corrections());
+            var data = correction.Payload!;
+            Assert.Equal(PolicyA, data["policyId"]);
+            Assert.Equal("platform", data["scriptType"]);
+            Assert.Equal("run-a", data["runId"]);
+            Assert.Equal("foreign", data["outcome"]);
+            Assert.Equal("stdout_differs", data["reason"]);
+            Assert.Equal("Success", data["result"]);
+            Assert.Equal(OwnStdout, data["stdout"]);
+            Assert.Equal(string.Empty, data["stderr"]);
+            Assert.Equal("1", data["previousExitCode"]);
+            Assert.Equal("0", data["registryErrorCode"]);
+            Assert.Equal("Warning", data[SignalPayloadKeys.Severity]);
+            Assert.Equal("true", data[SignalPayloadKeys.ImmediateUpload]);
+            Assert.DoesNotContain("exitCode", data.Keys);
+            Assert.Equal(1, f.Runs.Corrected);
+            Assert.Equal(0, f.Runs.Verified);
+
+            // The same save read again changes nothing.
+            f.Clock.Advance(TimeSpan.FromMinutes(1));
+            f.TrackerCaughtUp();
+            f.Observer.Tick("periodic");
+            Assert.Single(f.Corrections());
+        }
+
+        [Fact]
+        public void Confirmed_output_is_counted_and_emits_nothing()
+        {
+            var f = new Fixture();
+            f.Observer.Tick("baseline");
+            f.EmitRun(PolicyA, OwnStdout, 0, "run-a");
+            f.Save(Saved(OwnStdout));
+            f.Clock.Advance(TimeSpan.FromSeconds(1));
+            f.Observer.Tick("registry_change");
+            f.Clock.Advance(TimeSpan.FromSeconds(3));
+            f.TrackerCaughtUp();
+            f.Observer.Tick("periodic");
+
+            Assert.Empty(f.Corrections());
+            Assert.Equal(1, f.Runs.Verified);
+        }
+
+        [Fact]
+        public void Completed_output_is_an_info_event_that_keeps_the_exit_code()
+        {
+            var f = new Fixture();
+            f.Observer.Tick("baseline");
+            f.EmitRun(PolicyA, null, 0, "run-a");
+            f.Save(Saved(OwnStdout));
+            f.Clock.Advance(TimeSpan.FromSeconds(1));
+            f.Observer.Tick("registry_change");
+            f.Clock.Advance(TimeSpan.FromSeconds(3));
+            f.TrackerCaughtUp();
+            f.Observer.Tick("periodic");
+
+            var data = Assert.Single(f.Corrections()).Payload!;
+            Assert.Equal("repaired", data["outcome"]);
+            Assert.Equal("Info", data[SignalPayloadKeys.Severity]);
+            Assert.DoesNotContain("previousExitCode", data.Keys);
+        }
+
+        [Fact]
+        public void A_save_seen_before_its_run_was_emitted_waits_for_the_emit()
+        {
+            var f = new Fixture();
+            f.Observer.Tick("baseline");
+            f.Runs.NoteStarted(DeviceUser, PolicyA, f.Clock.UtcNow); // result held for its end block
+            f.Save(Saved(OwnStdout));
+            f.Observer.Tick("registry_change");
+            f.Clock.Advance(TimeSpan.FromSeconds(3));
+            f.TrackerCaughtUp();
+            f.Observer.Tick("periodic");
+            Assert.Equal(0, f.Runs.Verified + f.Runs.Corrected);
+
+            f.Runs.NoteEmitted(Emitted(PolicyA, ForeignStdout, 1, runId: "run-a"), f.Clock.UtcNow);
+            f.Clock.Advance(TimeSpan.FromSeconds(60));
+            f.Observer.Tick("periodic");
+            Assert.Equal("foreign", Assert.Single(f.Corrections()).Payload!["outcome"]);
+        }
+
+        [Fact]
+        public void A_save_no_run_claims_within_the_expiry_is_dropped()
+        {
+            var f = new Fixture();
+            f.Observer.Tick("baseline");
+            f.Save(Saved(OwnStdout));
+            f.Observer.Tick("registry_change");
+            f.Clock.Advance(ImeRegistryScriptResultObserver.PendingExpiry);
+            f.TrackerCaughtUp();
+            f.Runs.NoteStarted(DeviceUser, PolicyA, f.Clock.UtcNow);
+            f.Observer.Tick("periodic"); // waits for the emit — and expires
+
+            f.Runs.NoteEmitted(Emitted(PolicyA, ForeignStdout, 1, runId: "run-a"), f.Clock.UtcNow);
+            f.Clock.Advance(TimeSpan.FromSeconds(60));
+            f.TrackerCaughtUp();
+            f.Observer.Tick("periodic");
+            Assert.Empty(f.Corrections());
+        }
+
+        [Fact]
+        public void Saves_from_before_the_agent_started_are_the_silent_baseline()
+        {
+            var f = new Fixture();
+            f.EmitRun(PolicyA, ForeignStdout, 1, "run-a");
+            f.Save(Saved(OwnStdout));
+            f.TrackerCaughtUp();
+            f.Observer.Tick("baseline");
+            f.Clock.Advance(TimeSpan.FromMinutes(1));
+            f.TrackerCaughtUp();
+            f.Observer.Tick("periodic");
+
+            Assert.Empty(f.Corrections());
+            Assert.Equal(0, f.Runs.Verified + f.Runs.Corrected);
+        }
+
+        [Fact]
+        public void Corrections_beyond_the_cap_are_counted_but_not_emitted()
+        {
+            var f = new Fixture();
+            f.Observer.Tick("baseline");
+            var policies = Enumerable.Range(0, ImeRegistryScriptResultObserver.MaxCorrectionsPerSession + 3).Select(_ => Guid.NewGuid().ToString("D")).ToList();
+            foreach (var policy in policies)
+            {
+                f.EmitRun(policy, ForeignStdout, 1, "run-" + policy);
+                f.Save(Saved(OwnStdout, policy: policy));
+            }
+            f.Observer.Tick("registry_change");
+            f.Clock.Advance(TimeSpan.FromSeconds(3));
+            f.TrackerCaughtUp();
+            f.Observer.Tick("periodic");
+
+            Assert.Equal(ImeRegistryScriptResultObserver.MaxCorrectionsPerSession, f.Corrections().Count);
+            Assert.Equal(policies.Count, f.Runs.Corrected);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/OobeUpdateRegistrySnapshotTests.cs

@@ -0,0 +1,128 @@
+#nullable enable
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
+{
+    /// <summary>
+    /// The OOBE update registry snapshot (D-310, S4/S5): one readable, bounded line per key, for
+    /// agent.log and the <c>oobe_update_state</c> event. The registry read itself is a thin wrapper.
+    /// </summary>
+    public sealed class OobeUpdateRegistrySnapshotTests
+    {
+        private static KeyValuePair<string, object> Entry(string name, object value) => new KeyValuePair<string, object>(name, value);
+
+        [Fact]
+        public void Values_AreFormattedByType()
+        {
+            Assert.Equal("1", OobeUpdateRegistrySnapshot.FormatValue(1));
+            Assert.Equal("5000000000", OobeUpdateRegistrySnapshot.FormatValue(5000000000L));
+            Assert.Equal("Succeeded", OobeUpdateRegistrySnapshot.FormatValue("Succeeded"));
+            Assert.Equal("a|b", OobeUpdateRegistrySnapshot.FormatValue(new[] { "a", "b" }));
+            Assert.Equal("(binary 3 bytes)", OobeUpdateRegistrySnapshot.FormatValue(new byte[] { 1, 2, 3 }));
+            Assert.Equal("(null)", OobeUpdateRegistrySnapshot.FormatValue(null!));
+        }
+
+        [Fact]
+        public void LongValues_AreTruncated()
+        {
+            var formatted = OobeUpdateRegistrySnapshot.FormatValue(new string('x', 500));
+            Assert.Equal(OobeUpdateRegistrySnapshot.MaxValueLength + 1, formatted.Length);
+            Assert.EndsWith("…", formatted);
+        }
+
+        [Fact]
+        public void Entries_AreOrderedByName()
+        {
+            var line = OobeUpdateRegistrySnapshot.FormatEntries(new[]
+            {
+                Entry("ExpeditedUpdateStatus", 2),
+                Entry("EnableExpeditedUpdate", 1),
+                Entry("", "default"),
+            }, oobeOnly: false);
+
+            Assert.Equal("(default)=default, EnableExpeditedUpdate=1, ExpeditedUpdateStatus=2", line);
+        }
+
+        [Fact]
+        public void PolicyManagerSystemKey_KeepsOnlyOobeValues()
+        {
+            // That key holds every System policy of the device; only the OOBE ones matter here.
+            var line = OobeUpdateRegistrySnapshot.FormatEntries(new[]
+            {
+                Entry("AllowTelemetry", 1),
+                Entry("AllowOOBEUpdates", 1),
+                Entry("AllowOOBEUpdates_ProviderSet", 1),
+            }, oobeOnly: true);
+
+            Assert.Equal("AllowOOBEUpdates=1, AllowOOBEUpdates_ProviderSet=1", line);
+            Assert.Equal("(no OOBE values)", OobeUpdateRegistrySnapshot.FormatEntries(new[] { Entry("AllowTelemetry", 1) }, oobeOnly: true));
+            Assert.Equal("(no values)", OobeUpdateRegistrySnapshot.FormatEntries(new KeyValuePair<string, object>[0], oobeOnly: false));
+        }
+
+        [Fact]
+        public void ManyEntries_AreCapped_AndSaySo()
+        {
+            var entries = Enumerable.Range(0, OobeUpdateRegistrySnapshot.MaxEntries + 5)
+                .Select(i => Entry($"Value{i:000}", i));
+
+            var line = OobeUpdateRegistrySnapshot.FormatEntries(entries, oobeOnly: false);
+
+            Assert.EndsWith("… (+5 more)", line);
+        }
+
+        [Fact]
+        public void Describe_CountsOnlyOobeValues_OfThePolicyManagerSystemKey()
+        {
+            var policy = OobeUpdateRegistrySnapshot.Describe("policyManagerSystem", OobeUpdateRegistrySnapshot.PolicyManagerSystemKey,
+                new[] { Entry("AllowTelemetry", 1) }, new string[0]);
+            Assert.True(policy.Exists);
+            Assert.False(policy.HasValues);
+
+            var oobe = OobeUpdateRegistrySnapshot.Describe("policyManagerSystem", OobeUpdateRegistrySnapshot.PolicyManagerSystemKey,
+                new[] { Entry("AllowTelemetry", 1), Entry("AllowOOBEUpdates", 1) }, new string[0]);
+            Assert.True(oobe.HasValues);
+            Assert.Equal("AllowOOBEUpdates=1", oobe.Line);
+        }
+
+        [Fact]
+        public void Describe_SubkeysAlone_AreNoValues()
+        {
+            var state = OobeUpdateRegistrySnapshot.Describe("ndup", @"SOFTWARE\Microsoft\Windows\CurrentVersion\NDUP",
+                new KeyValuePair<string, object>[0], new[] { "Updates" });
+
+            Assert.False(state.HasValues);
+            Assert.Equal("(no values) | subkeys: Updates", state.Line);
+        }
+
+        [Fact]
+        public void Keys_HaveDistinctAliases()
+        {
+            // The aliases are the data keys of oobe_update_state.
+            Assert.Equal(OobeUpdateRegistrySnapshot.Keys.Length,
+                OobeUpdateRegistrySnapshot.Keys.Select(k => k.Alias).Distinct().Count());
+        }
+
+        [Fact]
+        public void Read_ReturnsEveryKey_FromTheRealRegistry()
+        {
+            var states = OobeUpdateRegistrySnapshot.Read();
+
+            Assert.Equal(OobeUpdateRegistrySnapshot.Keys.Select(k => k.Path), states.Select(s => s.Path));
+            Assert.All(states.Where(s => !s.Exists), s => Assert.False(s.HasValues));
+        }
+
+        [Fact]
+        public void Log_ToleratesMissingLoggerOrStates()
+        {
+            using var tmp = new TempDirectory();
+            OobeUpdateRegistrySnapshot.Log(new AgentLogger(tmp.Path, AgentLogLevel.Info), "test", OobeUpdateRegistrySnapshot.Read());
+            OobeUpdateRegistrySnapshot.Log(null!, "test", OobeUpdateRegistrySnapshot.Read());
+            OobeUpdateRegistrySnapshot.Log(new AgentLogger(tmp.Path, AgentLogLevel.Info), "test", null!);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/OobeUpdateTelemetryTests.cs

@@ -0,0 +1,259 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.Shared;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
+{
+    /// <summary>
+    /// Measurement telemetry of the OOBE update page (D-310): <c>oobe_update_page</c> per
+    /// update-page record and <c>oobe_update_state</c> for the registry behind it — Debug, bounded
+    /// per run, the state only when a key holds values and the content changed.
+    /// </summary>
+    public sealed class OobeUpdateTelemetryTests : IDisposable
+    {
+        private static readonly DateTime At = new DateTime(2026, 10, 2, 9, 0, 0, DateTimeKind.Utc);
+
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly FakeSignalIngressSink _sink = new FakeSignalIngressSink();
+        private IReadOnlyList<OobeUpdateRegistrySnapshot.KeyState> _registry = Array.Empty<OobeUpdateRegistrySnapshot.KeyState>();
+
+        public void Dispose() => _tmp.Dispose();
+
+        private OobeUpdateTelemetry Build(Func<IReadOnlyList<OobeUpdateRegistrySnapshot.KeyState>>? reader = null) =>
+            new OobeUpdateTelemetry("sess-oobe", "tenant-oobe",
+                new InformationalEventPost(_sink, new VirtualClock(At)),
+                new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                reader ?? (() => _registry));
+
+        private IReadOnlyList<FakeSignalIngressSink.PostedSignal> ByType(string eventType) =>
+            _sink.Posted.Where(p =>
+                p.Kind == DecisionSignalKind.InformationalEvent
+                && p.Payload != null
+                && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                && et == eventType).ToList();
+
+        private static IReadOnlyDictionary<string, object> Data(FakeSignalIngressSink.PostedSignal posted) =>
+            (IReadOnlyDictionary<string, object>)posted.TypedPayload!;
+
+        private static OobeUpdateRegistrySnapshot.KeyState Key(string alias, string? line) =>
+            line == null
+                ? new OobeUpdateRegistrySnapshot.KeyState(alias, $@"SOFTWARE\{alias}", exists: false, hasValues: false, line: null)
+                : new OobeUpdateRegistrySnapshot.KeyState(alias, $@"SOFTWARE\{alias}", exists: true, hasValues: true, line: line);
+
+        // ------------------------------------------------------------- oobe_update_page ----
+
+        [Fact]
+        public void Page_IsReported_WithItsEventTime_AndFields()
+        {
+            Build().ReportPage(
+                new OobeUpdatePageRecord(OobeUpdatePageRecord.PageStopped, 62405, page: "OobeNDUP", result: "success"),
+                At.AddMinutes(-3), isBackfill: true);
+
+            var page = Assert.Single(ByType(Constants.EventTypes.OobeUpdatePage));
+            Assert.Equal(At.AddMinutes(-3), page.OccurredAtUtc);
+            Assert.Equal("Debug", page.Payload![SignalPayloadKeys.Severity]);
+            var data = Data(page);
+            Assert.Equal("page_stopped", data["cxhEvent"]);
+            Assert.Equal("OobeNDUP", data["page"]);
+            Assert.Equal("success", data["result"]);
+            Assert.Equal(true, data["backfill"]);
+            Assert.Equal(1, data["occurrence"]);
+            Assert.False(data.ContainsKey("value"));
+        }
+
+        [Fact]
+        public void EventName_CarriesItsSafeValue()
+        {
+            Build().ReportPage(
+                new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, 62407, name: "ExpeditedUpdate_isNDUPAllowedByCSPSucceeded", value: "true"),
+                At, isBackfill: false);
+
+            var data = Data(Assert.Single(ByType(Constants.EventTypes.OobeUpdatePage)));
+            Assert.Equal("ExpeditedUpdate_isNDUPAllowedByCSPSucceeded", data["name"]);
+            Assert.Equal("true", data["value"]);
+        }
+
+        [Fact]
+        public void SamePageOrName_IsReportedAtMostThreeTimes()
+        {
+            var telemetry = Build();
+            for (var i = 0; i < 10; i++)
+            {
+                telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, 62406, name: "ExpeditedUpdate_progress"), At.AddSeconds(i), isBackfill: false);
+            }
+            telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.PageStopped, 62405, page: "OobeNDUP", result: "success"), At.AddMinutes(1), isBackfill: false);
+
+            var pages = ByType(Constants.EventTypes.OobeUpdatePage);
+            Assert.Equal(OobeUpdateTelemetry.MaxPageEventsPerKey + 1, pages.Count);
+            Assert.Equal(new object[] { 1, 2, 3 }, pages.Take(3).Select(p => Data(p)["occurrence"]).ToArray());
+            // The repeats do not crowd out the page end.
+            Assert.Equal("page_stopped", Data(pages.Last())["cxhEvent"]);
+        }
+
+        [Fact]
+        public void PageEvents_AreCappedPerRun_AndTheCapIsMarkedOnce()
+        {
+            var telemetry = Build();
+            for (var i = 0; i < OobeUpdateTelemetry.MaxPageEventsPerRun + 20; i++)
+            {
+                telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, 62406, name: $"ExpeditedUpdate_step{i}"), At.AddSeconds(i), isBackfill: false);
+            }
+
+            var pages = ByType(Constants.EventTypes.OobeUpdatePage);
+            Assert.Equal(OobeUpdateTelemetry.MaxPageEventsPerRun + 1, pages.Count);
+            // A name missing after the marker proves nothing — the rules check for it.
+            var marker = Data(pages.Last());
+            Assert.Equal(OobeUpdatePageRecord.NamesCapped, marker["cxhEvent"]);
+            Assert.Equal(false, marker["backfill"]);
+            Assert.Equal(OobeUpdateTelemetry.MaxPageEventsPerRun, marker["limit"]);
+            Assert.Equal(At.AddSeconds(OobeUpdateTelemetry.MaxPageEventsPerRun), pages.Last().OccurredAtUtc); // the first name over the budget
+        }
+
+        [Fact]
+        public void BackfilledNames_HaveTheirOwnBudget()
+        {
+            // The records from before the agent started cannot spend the live page's budget.
+            var telemetry = Build();
+            for (var i = 0; i < OobeUpdateTelemetry.MaxBackfillPageEventsPerRun + 5; i++)
+            {
+                telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, 62406, name: $"ExpeditedUpdate_old{i}"), At.AddMinutes(-30), isBackfill: true);
+            }
+
+            Assert.True(telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, 62406, name: "ExpeditedUpdate_live"), At, isBackfill: false));
+
+            var markers = ByType(Constants.EventTypes.OobeUpdatePage)
+                .Where(p => (string)Data(p)["cxhEvent"] == OobeUpdatePageRecord.NamesCapped).ToList();
+            var marker = Assert.Single(markers);
+            Assert.Equal(true, Data(marker)["backfill"]);
+            Assert.Equal(OobeUpdateTelemetry.MaxBackfillPageEventsPerRun, Data(marker)["limit"]);
+        }
+
+        [Fact]
+        public void PageStartAndStop_AreReported_AfterTheNameBudgetIsSpent()
+        {
+            // The time attribution reads the update's span from the page start and stop.
+            var telemetry = Build();
+            for (var i = 0; i < OobeUpdateTelemetry.MaxPageEventsPerRun; i++)
+            {
+                Assert.True(telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, 62406, name: $"ExpeditedUpdate_step{i}"), At, isBackfill: false));
+            }
+
+            Assert.False(telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, 62406, name: "ExpeditedUpdate_late"), At, isBackfill: false));
+            Assert.False(telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, 62406, name: "ExpeditedUpdate_later"), At, isBackfill: false));
+            Assert.True(telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.PageStarted, 62404, page: "RebootNDUP"), At.AddMinutes(1), isBackfill: false));
+            Assert.True(telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.PageStopped, 62405, page: "RebootNDUP", result: "success"), At.AddMinutes(2), isBackfill: false));
+
+            var pages = ByType(Constants.EventTypes.OobeUpdatePage);
+            Assert.Equal(OobeUpdateTelemetry.MaxPageEventsPerRun + 3, pages.Count);
+            Assert.Equal(new object[] { OobeUpdatePageRecord.NamesCapped, "page_started", "page_stopped" },
+                pages.Skip(OobeUpdateTelemetry.MaxPageEventsPerRun).Select(p => Data(p)["cxhEvent"]).ToArray());
+        }
+
+        [Fact]
+        public void SamePageStart_IsReportedAtMostThreeTimes()
+        {
+            // Outside the run budget, but a page that restarts in a loop still cannot flood.
+            var telemetry = Build();
+            var reported = Enumerable.Range(0, 10)
+                .Count(i => telemetry.ReportPage(new OobeUpdatePageRecord(OobeUpdatePageRecord.PageStarted, 62404, page: "OobeNDUP"), At.AddMinutes(i), isBackfill: false));
+
+            Assert.Equal(OobeUpdateTelemetry.MaxPageEventsPerKey, reported);
+        }
+
+        // ------------------------------------------------------------ oobe_update_state ----
+
+        [Fact]
+        public void State_WithoutValues_IsNotReported()
+        {
+            _registry = new[] { Key("setupOobeNdup", null), Key("policiesOobe", null) };
+
+            Build().ReportState(OobeUpdateTelemetry.Moments.AgentStart);
+
+            Assert.Empty(ByType(Constants.EventTypes.OobeUpdateState));
+        }
+
+        [Fact]
+        public void State_ReportsOnlyKeysWithValues_UnderTheirAlias()
+        {
+            _registry = new[]
+            {
+                Key("setupOobeNdup", "EnableExpeditedUpdate=1, EnableExpeditedUpdateSyncDownloadCompleted=1"),
+                Key("ndup", null),
+                new OobeUpdateRegistrySnapshot.KeyState("policyManagerSystem", "x", exists: true, hasValues: false, line: "(no OOBE values)"),
+                Key("espSetupPolicy", "InstallQualityUpdates=1"),
+            };
+
+            Build().ReportState(OobeUpdateTelemetry.Moments.UpdatePageStopped, "OobeNDUP");
+
+            var state = Assert.Single(ByType(Constants.EventTypes.OobeUpdateState));
+            Assert.Equal("Debug", state.Payload![SignalPayloadKeys.Severity]);
+            var data = Data(state);
+            Assert.Equal("update_page_stopped", data["moment"]);
+            Assert.Equal("OobeNDUP", data["page"]);
+            Assert.Equal(2, data["keysWithValues"]);
+            Assert.Equal("EnableExpeditedUpdate=1, EnableExpeditedUpdateSyncDownloadCompleted=1", data["setupOobeNdup"]);
+            Assert.Equal("InstallQualityUpdates=1", data["espSetupPolicy"]);
+            Assert.False(data.ContainsKey("ndup"));
+            Assert.False(data.ContainsKey("policyManagerSystem"));
+        }
+
+        [Fact]
+        public void UnchangedState_IsReportedOnce_AChangeAgain()
+        {
+            var telemetry = Build();
+            _registry = new[] { Key("espSetupPolicy", "InstallQualityUpdates=1") };
+
+            telemetry.ReportState(OobeUpdateTelemetry.Moments.AgentStart);
+            telemetry.ReportState(OobeUpdateTelemetry.Moments.UpdatePageStarted, "OobeNDUP");
+            _registry = new[] { Key("espSetupPolicy", "InstallQualityUpdates=1"), Key("setupOobeNdup", "EnableExpeditedUpdate=1") };
+            telemetry.ReportState(OobeUpdateTelemetry.Moments.UpdatePageStopped, "OobeNDUP");
+            telemetry.ReportState(OobeUpdateTelemetry.Moments.AgentStop);
+
+            var states = ByType(Constants.EventTypes.OobeUpdateState);
+            Assert.Equal(new object[] { "agent_start", "update_page_stopped" }, states.Select(s => Data(s)["moment"]).ToArray());
+        }
+
+        [Fact]
+        public void StateEvents_AreCappedPerRun()
+        {
+            var telemetry = Build();
+            for (var i = 0; i < OobeUpdateTelemetry.MaxStateEventsPerRun + 4; i++)
+            {
+                _registry = new[] { Key("setupOobeNdup", $"ExpeditedUpdateStatus={i}") };
+                telemetry.ReportState(OobeUpdateTelemetry.Moments.UpdatePageStarted, "OobeNDUP");
+            }
+
+            Assert.Equal(OobeUpdateTelemetry.MaxStateEventsPerRun, ByType(Constants.EventTypes.OobeUpdateState).Count);
+        }
+
+        [Fact]
+        public void LongLines_AreTruncated()
+        {
+            _registry = new[] { Key("ndupUpdates", new string('x', 3000)) };
+
+            Build().ReportState(OobeUpdateTelemetry.Moments.AgentStart);
+
+            var line = (string)Data(Assert.Single(ByType(Constants.EventTypes.OobeUpdateState)))["ndupUpdates"];
+            Assert.Equal(OobeUpdateTelemetry.MaxStateLineLength + 1, line.Length);
+            Assert.EndsWith("…", line);
+        }
+
+        [Fact]
+        public void FailingRegistryRead_ReportsNothing_AndDoesNotThrow()
+        {
+            Build(() => throw new UnauthorizedAccessException("denied")).ReportState(OobeUpdateTelemetry.Moments.AgentStart);
+
+            Assert.Empty(_sink.Posted);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/ProvisioningStatusTrackerAccountSetupActivityTests.cs

@@ -83,6 +83,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
             using var f = new Fixture();
             Assert.False(f.Tracker.HasAccountSetupActivity);
             Assert.False(f.Tracker.HasAccountSetupProgress);
+            Assert.Null(f.Tracker.AccountSetupProgressIfRead);
         }
 
         [Fact]
@@ -97,6 +98,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
 
             Assert.True(f.Tracker.HasAccountSetupActivity);
             Assert.False(f.Tracker.HasAccountSetupProgress);
+            // Read and untouched — the only state the WhiteGlove sealing gate treats as "false".
+            Assert.False(f.Tracker.AccountSetupProgressIfRead);
         }
 
         [Fact]
@@ -108,6 +111,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
 
             Assert.True(f.Tracker.HasAccountSetupActivity);
             Assert.True(f.Tracker.HasAccountSetupProgress);
+            Assert.True(f.Tracker.AccountSetupProgressIfRead);
         }
 
         [Theory]
@@ -138,5 +142,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
 
             Assert.False(f.Tracker.HasAccountSetupProgress);
         }
+
+        [Fact]
+        public void OnlyDeviceSetupRead_AccountSetupProgressIsUnknown()
+        {
+            // Adversarial for the WhiteGlove sealing gate: the tracker holds DeviceSetup data but
+            // has not read the AccountSetup category — that must be "unknown", never "untouched".
+            using var f = new Fixture();
+            f.Tracker.ProcessCategoryStatusForTest("DeviceSetupCategory.Status",
+                "{\"categoryState\":\"inProgress\",\"DeviceSetup.AppsSubcategory\":{\"subcategoryState\":\"inProgress\"}}");
+
+            Assert.Null(f.Tracker.AccountSetupProgressIfRead);
+            Assert.False(f.Tracker.HasAccountSetupProgress);
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/ServicingTrackerTests.cs

@@ -0,0 +1,289 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.DecisionCore.State;
+using AutopilotMonitor.Shared;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
+{
+    /// <summary>
+    /// ServicingTracker (D-310) — the CBS servicing steps of OS updates from the Setup log. The
+    /// sequence and XML shapes are those Windows 11 writes for a cumulative update installed by
+    /// <c>UpdateAgentLCU</c>: initiate Absent → Staged, Staged reached, initiate Staged → Installed,
+    /// restart required, Installed reached after the restart.
+    /// </summary>
+    public sealed class ServicingTrackerTests : IDisposable
+    {
+        private static readonly DateTime T0 = new DateTime(2026, 9, 25, 18, 52, 37, DateTimeKind.Utc);
+        private const string Kb = "KB5099999";
+
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly FakeSignalIngressSink _sink = new FakeSignalIngressSink();
+        private readonly UpdateActivityTally _tally = new UpdateActivityTally();
+        private readonly List<(string Step, string Update, DateTime At)> _osActivity = new List<(string, string, DateTime)>();
+        private readonly ServicingTracker _tracker;
+        private long _nextRecordId = 1200;
+
+        public ServicingTrackerTests()
+        {
+            _tracker = NewTracker(stateDirectory: null);
+        }
+
+        public void Dispose() => _tmp.Dispose();
+
+        private ServicingTracker NewTracker(string? stateDirectory) =>
+            new ServicingTracker(
+                sessionId: "sess-cbs",
+                tenantId: "tenant-cbs",
+                post: new InformationalEventPost(_sink, new VirtualClock(T0)),
+                logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                backfillEnabled: false,
+                stateDirectory: stateDirectory,
+                tally: _tally,
+                onOsUpdateActivity: (step, update, at) => _osActivity.Add((step, update, at)));
+
+        private void Process(
+            int eventId,
+            DateTime at,
+            string? initialState = null,
+            string? targetState = "Installed",
+            string? errorCode = null,
+            string? client = "UpdateAgentLCU",
+            string? package = Kb,
+            long? recordId = null,
+            ServicingTracker? tracker = null,
+            bool isBackfill = false)
+        {
+            (tracker ?? _tracker).ProcessEvent(
+                eventId: eventId,
+                recordId: recordId ?? _nextRecordId++,
+                timeCreatedUtc: at,
+                package: package,
+                initialState: initialState,
+                targetState: targetState,
+                errorCode: errorCode,
+                client: client,
+                isBackfill: isBackfill);
+        }
+
+        private IReadOnlyList<FakeSignalIngressSink.PostedSignal> Servicing() =>
+            _sink.Posted.Where(p =>
+                p.Kind == DecisionSignalKind.InformationalEvent
+                && p.Payload != null
+                && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                && et == Constants.EventTypes.WindowsUpdateServicing).ToList();
+
+        private static IReadOnlyDictionary<string, object> Data(FakeSignalIngressSink.PostedSignal s) =>
+            (IReadOnlyDictionary<string, object>)s.TypedPayload!;
+
+        [Fact]
+        public void CumulativeUpdateSequence_ListsEveryStep_AndReportsTheEngineSteps()
+        {
+            Process(ServicingTracker.EventId_InitiatingChanges, T0, initialState: "Absent", targetState: "Staged");
+            Process(ServicingTracker.EventId_StateReached, T0.AddMinutes(4), targetState: "Staged", errorCode: "0x0");
+            Process(ServicingTracker.EventId_InitiatingChanges, T0.AddMinutes(29), initialState: "Staged", targetState: "Installed");
+            Process(ServicingTracker.EventId_RebootRequired, T0.AddMinutes(33), targetState: "Installed", errorCode: "0x0");
+            // Written after the restart.
+            Process(ServicingTracker.EventId_StateReached, T0.AddMinutes(41), targetState: "Installed", errorCode: "0x0");
+
+            var rows = Servicing();
+            Assert.Equal(
+                new[] { "initiating", "state_reached", "initiating", "reboot_required", "state_reached" },
+                rows.Select(s => (string)Data(s)["step"]).ToArray());
+            Assert.All(rows, s => Assert.Equal("Info", s.Payload![SignalPayloadKeys.Severity]));
+            Assert.All(rows, s => Assert.Equal("ServicingWatcher", s.Payload![SignalPayloadKeys.Source]));
+            Assert.All(rows, s => Assert.Equal(Kb, Data(s)["package"]));
+            Assert.All(rows, s => Assert.Equal("UpdateAgentLCU", Data(s)["client"]));
+            // ErrorCode 0x0 is success, not a decoded HRESULT.
+            Assert.All(rows, s => Assert.False(Data(s).ContainsKey("hresult")));
+            Assert.Equal("Absent", Data(rows[0])["initialState"]);
+            Assert.Equal("Staged", Data(rows[0])["targetState"]);
+            Assert.Equal(T0.AddMinutes(33), rows[3].OccurredAtUtc);
+            Assert.Contains("needs a restart", rows[3].Payload![SignalPayloadKeys.Message]);
+
+            Assert.Equal(
+                new[]
+                {
+                    OsUpdateSteps.StagingStarted, OsUpdateSteps.Staged, OsUpdateSteps.InstallStarted,
+                    OsUpdateSteps.RebootRequired, OsUpdateSteps.Installed,
+                },
+                _osActivity.Select(a => a.Step).ToArray());
+            Assert.All(_osActivity, a => Assert.Equal(Kb, a.Update));
+            Assert.Equal(T0.AddMinutes(29), _osActivity[2].At);
+        }
+
+        [Theory]
+        [InlineData("CbsTask")]
+        [InlineData("DISM Package Manager Provider")]
+        [InlineData("")]
+        [InlineData(null)]
+        public void NonOsClients_AreCountedNotListed(string? client)
+        {
+            // CBS maintenance writes hundreds of these in seconds; language packs and features on
+            // demand installed by apps are not the OOBE update either.
+            Process(ServicingTracker.EventId_InitiatingChanges, T0, initialState: "Staged", targetState: "Installed",
+                client: client, package: "Microsoft-Windows-Telnet-Client-FOD-en-US");
+            Process(ServicingTracker.EventId_StateReached, T0, targetState: "Installed", errorCode: "0x0",
+                client: client, package: "Microsoft-Windows-Telnet-Client-FOD-en-US");
+
+            Assert.Empty(_sink.Posted);
+            Assert.Empty(_osActivity);
+            var counts = _tally.Snapshot().ToDictionary(kv => kv.Key, kv => kv.Value);
+            Assert.Equal(1, counts["servicing_other_1"]);
+            Assert.Equal(1, counts["servicing_other_2"]);
+        }
+
+        [Fact]
+        public void WindowsUpdateAgentClient_IsAnOsClient()
+        {
+            Process(ServicingTracker.EventId_RebootRequired, T0, client: "WindowsUpdateAgent", errorCode: "0x0");
+
+            Assert.Single(Servicing());
+            Assert.Equal(OsUpdateSteps.RebootRequired, Assert.Single(_osActivity).Step);
+        }
+
+        [Fact]
+        public void ChangeFailed_EmitsWarning_WithDecodedHResult()
+        {
+            Process(ServicingTracker.EventId_ChangeFailed, T0, targetState: "Installed", errorCode: "0x800f0922");
+
+            var s = Assert.Single(Servicing());
+            Assert.Equal("Warning", s.Payload![SignalPayloadKeys.Severity]);
+            var data = Data(s);
+            Assert.Equal("failed", data["step"]);
+            Assert.Equal("0x800F0922", data["hresult"]);
+            Assert.Equal("CBS_E_INSTALLERS_FAILED", data["hresultSymbol"]);
+            Assert.Contains("FAILED", s.Payload![SignalPayloadKeys.Message]);
+            Assert.Equal(OsUpdateSteps.Failed, Assert.Single(_osActivity).Step);
+        }
+
+        [Fact]
+        public void PartiallyInstalled_IsAFailure_AndSaysSo()
+        {
+            Process(ServicingTracker.EventId_PartiallyInstalled, T0, targetState: "Installed", errorCode: "0x800f0922");
+
+            var s = Assert.Single(Servicing());
+            Assert.Equal("failed", Data(s)["step"]);
+            Assert.Contains("partially installed", s.Payload![SignalPayloadKeys.Message]);
+            Assert.Equal(OsUpdateSteps.Failed, Assert.Single(_osActivity).Step);
+        }
+
+        [Fact]
+        public void ChangeTowardsAnotherState_IsListed_ButIsNoEngineStep()
+        {
+            // Removing a superseded package is servicing, not progress of the update install.
+            Process(ServicingTracker.EventId_InitiatingChanges, T0, initialState: "Installed", targetState: "Absent");
+
+            Assert.Single(Servicing());
+            Assert.Empty(_osActivity);
+        }
+
+        [Fact]
+        public void BackfilledRecord_KeepsItsEventTime()
+        {
+            var earlier = T0.AddMinutes(-20);
+            Process(ServicingTracker.EventId_InitiatingChanges, earlier, initialState: "Absent", targetState: "Staged", isBackfill: true);
+
+            var s = Assert.Single(Servicing());
+            Assert.Equal(earlier, s.OccurredAtUtc);
+            Assert.Equal(true, Data(s)["backfilled"]);
+            Assert.Equal(earlier, Assert.Single(_osActivity).At);
+        }
+
+        [Fact]
+        public void Watermark_SkipsEmittedRecordsAfterRestart()
+        {
+            var first = NewTracker(_tmp.Path);
+            Process(ServicingTracker.EventId_RebootRequired, T0, errorCode: "0x0", recordId: 1205, tracker: first);
+
+            var second = NewTracker(_tmp.Path);
+            second.LoadWatermark();
+            Process(ServicingTracker.EventId_RebootRequired, T0, errorCode: "0x0", recordId: 1205, tracker: second, isBackfill: true);
+            Process(ServicingTracker.EventId_StateReached, T0.AddMinutes(8), errorCode: "0x0", recordId: 1207, tracker: second);
+
+            Assert.Equal(new[] { "reboot_required", "state_reached" }, Servicing().Select(s => (string)Data(s)["step"]).ToArray());
+        }
+
+        [Fact]
+        public void SameRecordDeliveredTwice_IsListedOnce()
+        {
+            Process(ServicingTracker.EventId_RebootRequired, T0, errorCode: "0x0", recordId: 1205);
+            Process(ServicingTracker.EventId_RebootRequired, T0, errorCode: "0x0", recordId: 1205);
+
+            Assert.Single(Servicing());
+            Assert.Single(_osActivity);
+        }
+
+        [Fact]
+        public void ParseUserData_ReadsBothCbsPayloadShapes()
+        {
+            const string initiate =
+                "<Event xmlns='http://schemas.microsoft.com/win/2004/08/events/event'><System><Provider Name='Microsoft-Windows-Servicing' Guid='{bd12f3b8-fc40-4a61-a307-b7a013a069c1}'/>" +
+                "<EventID>1</EventID><Version>0</Version><Level>0</Level><Task>1</Task><Opcode>0</Opcode><Keywords>0x8000000000000000</Keywords>" +
+                "<TimeCreated SystemTime='2026-09-25T19:21:42.4486782Z'/><EventRecordID>1203</EventRecordID><Channel>Setup</Channel><Computer>DESKTOP-TEST</Computer>" +
+                "<Security UserID='S-1-5-18'/></System><UserData><CbsPackageInitiateChanges xmlns='http://manifests.microsoft.com/win/2004/08/windows/setup_provider'>" +
+                "<PackageIdentifier>KB5099999</PackageIdentifier><InitialPackageState>5064</InitialPackageState><InitialPackageStateTextized>Staged</InitialPackageStateTextized>" +
+                "<IntendedPackageState>5112</IntendedPackageState><IntendedPackageStateTextized>Installed</IntendedPackageStateTextized><Client>UpdateAgentLCU</Client>" +
+                "</CbsPackageInitiateChanges></UserData></Event>";
+            const string changeState =
+                "<Event xmlns='http://schemas.microsoft.com/win/2004/08/events/event'><System><Provider Name='Microsoft-Windows-Servicing' Guid='{bd12f3b8-fc40-4a61-a307-b7a013a069c1}'/>" +
+                "<EventID>4</EventID><TimeCreated SystemTime='2026-09-25T19:26:07.1381462Z'/><EventRecordID>1205</EventRecordID><Channel>Setup</Channel></System>" +
+                "<UserData><CbsPackageChangeState xmlns='http://manifests.microsoft.com/win/2004/08/windows/setup_provider'><PackageIdentifier>KB5099999</PackageIdentifier>" +
+                "<IntendedPackageState>5112</IntendedPackageState><IntendedPackageStateTextized>Installed</IntendedPackageStateTextized><ErrorCode>0x0</ErrorCode>" +
+                "<Client>UpdateAgentLCU</Client></CbsPackageChangeState></UserData></Event>";
+
+            var a = ServicingTracker.ParseUserData(initiate);
+            Assert.Equal("KB5099999", a["PackageIdentifier"]);
+            Assert.Equal("Staged", a["InitialPackageStateTextized"]);
+            Assert.Equal("Installed", a["IntendedPackageStateTextized"]);
+            Assert.Equal("UpdateAgentLCU", a["client"]); // case-insensitive
+            Assert.False(a.ContainsKey("ErrorCode"));
+
+            var b = ServicingTracker.ParseUserData(changeState);
+            Assert.Equal("Installed", b["IntendedPackageStateTextized"]);
+            Assert.Equal("0x0", b["ErrorCode"]);
+            Assert.False(b.ContainsKey("InitialPackageStateTextized"));
+        }
+
+        [Fact]
+        public void ParseUserData_MalformedOrWithoutUserData_ReturnsEmpty_NeverThrows()
+        {
+            Assert.Empty(ServicingTracker.ParseUserData(null));
+            Assert.Empty(ServicingTracker.ParseUserData(""));
+            Assert.Empty(ServicingTracker.ParseUserData("<not-xml"));
+            Assert.Empty(ServicingTracker.ParseUserData("<Event><System><EventID>1</EventID></System></Event>"));
+        }
+
+        [Fact]
+        public void Watermark_PersistsOnlyAfterTheEngineSignalWasHandedOver()
+        {
+            // "Reboot required" is written right before the update's restart: its engine signal
+            // must be on its way before the watermark tells the next run's backfill to skip it.
+            var path = System.IO.Path.Combine(_tmp.Path, ServicingTracker.WatermarkStateFileName);
+            bool? watermarkOnDiskAtSignal = null;
+            var tracker = new ServicingTracker(
+                sessionId: "sess-cbs",
+                tenantId: "tenant-cbs",
+                post: new InformationalEventPost(_sink, new VirtualClock(T0)),
+                logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                backfillEnabled: false,
+                stateDirectory: _tmp.Path,
+                tally: _tally,
+                onOsUpdateActivity: (step, update, at) => watermarkOnDiskAtSignal = System.IO.File.Exists(path));
+
+            Process(ServicingTracker.EventId_RebootRequired, T0, errorCode: "0x0", tracker: tracker);
+
+            Assert.False(watermarkOnDiskAtSignal);
+            Assert.True(System.IO.File.Exists(path));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/StallProbeHelloWaitGuardTests.cs

@@ -0,0 +1,123 @@
+#nullable enable
+using System;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.Shared;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
+{
+    /// <summary>
+    /// A tenant-extended Hello wait runs up to 60 min — the default session_stalled threshold. While
+    /// it is pending the session waits on a bounded timer that resolves it either way, so the stall
+    /// probe holds the report back instead of flagging the session Stalled; once the wait is over
+    /// and the session is still idle the report fires, and real activity drops it. The collector
+    /// runs with no scan sources, so only the session_stalled decision is exercised.
+    /// </summary>
+    public sealed class StallProbeHelloWaitGuardTests
+    {
+        private static readonly DateTime Fixed = new DateTime(2026, 9, 29, 8, 0, 0, DateTimeKind.Utc);
+        private const double IdleAtStallThreshold = 60;
+
+        [Fact]
+        public void Session_stalled_is_held_back_while_the_hello_wait_is_pending()
+        {
+            using var tmp = new TempDirectory();
+            var ingress = new FakeSignalIngressSink();
+            var collector = NewCollector(tmp, ingress, helloWaitPending: () => true);
+
+            collector.CheckAndRunProbes(IdleAtStallThreshold);
+            collector.CheckAndRunProbes(IdleAtStallThreshold + 1);
+
+            Assert.Equal(0, StalledCount(ingress));
+        }
+
+        [Fact]
+        public void Held_back_report_fires_once_the_hello_wait_is_over_and_the_session_is_still_idle()
+        {
+            using var tmp = new TempDirectory();
+            var ingress = new FakeSignalIngressSink();
+            var pending = true;
+            var collector = NewCollector(tmp, ingress, helloWaitPending: () => pending);
+
+            collector.CheckAndRunProbes(IdleAtStallThreshold);
+            Assert.Equal(0, StalledCount(ingress));
+
+            // hello_safety resolved (a deadline fire is no activity, so no ResetProbes): the next
+            // tick emits the held-back report — once.
+            pending = false;
+            collector.CheckAndRunProbes(IdleAtStallThreshold + 1);
+            collector.CheckAndRunProbes(IdleAtStallThreshold + 2);
+
+            Assert.Equal(1, StalledCount(ingress));
+        }
+
+        [Fact]
+        public void Real_activity_drops_the_held_back_report()
+        {
+            using var tmp = new TempDirectory();
+            var ingress = new FakeSignalIngressSink();
+            var pending = true;
+            var collector = NewCollector(tmp, ingress, helloWaitPending: () => pending);
+
+            collector.CheckAndRunProbes(IdleAtStallThreshold);
+            pending = false;
+            collector.ResetProbes();
+            collector.CheckAndRunProbes(1);
+            Assert.Equal(0, StalledCount(ingress));
+
+            // A new idle window reaches the threshold again — the fire-once report is still unused.
+            collector.CheckAndRunProbes(IdleAtStallThreshold);
+            Assert.Equal(1, StalledCount(ingress));
+        }
+
+        [Fact]
+        public void Without_a_hello_wait_probe_session_stalled_fires_as_before()
+        {
+            using var tmp = new TempDirectory();
+            var ingress = new FakeSignalIngressSink();
+            var collector = NewCollector(tmp, ingress, helloWaitPending: null);
+
+            collector.CheckAndRunProbes(IdleAtStallThreshold);
+
+            Assert.Equal(1, StalledCount(ingress));
+        }
+
+        [Fact]
+        public void A_throwing_hello_wait_probe_never_costs_the_stall_report()
+        {
+            using var tmp = new TempDirectory();
+            var ingress = new FakeSignalIngressSink();
+            var collector = NewCollector(tmp, ingress, helloWaitPending: () => throw new InvalidOperationException("probe down"));
+
+            collector.CheckAndRunProbes(IdleAtStallThreshold);
+
+            Assert.Equal(1, StalledCount(ingress));
+        }
+
+        private static StallProbeCollector NewCollector(TempDirectory tmp, FakeSignalIngressSink ingress, Func<bool>? helloWaitPending) =>
+            new StallProbeCollector(
+                sessionId: "S1",
+                tenantId: "T1",
+                post: new InformationalEventPost(ingress, new VirtualClock(Fixed)),
+                logger: new AgentLogger(tmp.Path, AgentLogLevel.Info),
+                thresholdsMinutes: new[] { 60 },
+                traceIndices: Array.Empty<int>(),
+                sources: Array.Empty<string>(),
+                sessionStalledAfterProbeIndex: 1,
+                helloWaitPending: helloWaitPending);
+
+        private static int StalledCount(FakeSignalIngressSink ingress) =>
+            ingress.Posted.Count(p =>
+                p.Kind == DecisionSignalKind.InformationalEvent
+                && p.Payload != null
+                && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                && et == Constants.EventTypes.SessionStalled);
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/WindowsUpdateClassifierTests.cs

@@ -0,0 +1,85 @@
+#nullable enable
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
+{
+    /// <summary>
+    /// WindowsUpdateClassifier (D-310) — decides which Windows Update client events are listed one
+    /// by one (OS updates) and which are only counted (Store, Defender, everything else). The
+    /// titles are the shapes the WU client writes on Windows 11 GA and Insider builds.
+    /// </summary>
+    public sealed class WindowsUpdateClassifierTests
+    {
+        [Theory]
+        [InlineData("2026-09 Cumulative Update for Windows 11, version 25H2 for x64-based Systems (KB5099999)")]
+        [InlineData("2026-09 Cumulative Update Preview for Windows 11, version 24H2 for x64-based Systems (KB5099998)")]
+        [InlineData("2026-09 Dynamic Update for Windows 11, version 25H2 for x64-based Systems (KB5099997)")]
+        [InlineData("2026-09 Servicing Stack Update for Windows 11, version 25H2 for x64-based Systems (KB5099996)")]
+        [InlineData("Windows 11 Insider Preview Quality Update (26220.9568)")]
+        [InlineData("Windows 11 Insider Preview Feature Update (26220.9022)")]
+        [InlineData("Windows 11, version 25H2 Upgrade")]
+        [InlineData("2026-09 .NET Framework Security Update (KB5099995)")]
+        [InlineData("2026-08 .NET Framework Preview Update (KB5099994)")]
+        [InlineData("Windows Malicious Software Removal Tool x64 - v5.145 (KB890830)")]
+        public void WindowsAndDotNetFrameworkUpdates_AreOs(string title)
+        {
+            Assert.Equal(WindowsUpdateClassifier.Os, WindowsUpdateClassifier.Classify(title, serviceGuid: null));
+        }
+
+        [Theory]
+        [InlineData("Security Intelligence Update for Microsoft Defender Antivirus - KB2267602 (Version 1.459.505.0) - Current Channel (Broad)")]
+        [InlineData("Update for Microsoft Defender Antivirus antimalware platform - KB4052623 (Version 4.18.26080.4) - Current Channel (Staged)")]
+        // Names "Windows" and "Update" — Defender must still win.
+        [InlineData("Windows 10/11 - Update for Microsoft Defender for Endpoint - KB5005292 (Version 10.8838.26060.15013) - Current Channel (Staged)")]
+        public void DefenderUpdates_AreDefender(string title)
+        {
+            Assert.Equal(WindowsUpdateClassifier.Defender, WindowsUpdateClassifier.Classify(title, serviceGuid: null));
+        }
+
+        [Theory]
+        [InlineData("9NSTH9KHZDLQ-Microsoft.UI.Xaml.2.8")]
+        [InlineData("9NBLGGH4NNS1-Microsoft.DesktopAppInstaller")]
+        // Upper-case "WINDOWS" inside the package name must not make it an OS update.
+        [InlineData("9WZDNCRFHVN5-MICROSOFT.WINDOWSCALCULATOR")]
+        [InlineData("9WZDNCRFHWKN-MICROSOFT.WINDOWSSOUNDRECORDER")]
+        [InlineData("ApplicationSet-9WZDNCRFJ3Q2-Microsoft.BingWeather")]
+        public void StoreProductTitles_AreStore(string title)
+        {
+            Assert.Equal(WindowsUpdateClassifier.Store, WindowsUpdateClassifier.Classify(title, serviceGuid: null));
+        }
+
+        [Theory]
+        [InlineData("{855e8a7c-ecb4-4ca3-b045-1dfa50104289}")]
+        [InlineData("{855E8A7C-ECB4-4CA3-B045-1DFA50104289}")]
+        [InlineData("855e8a7c-ecb4-4ca3-b045-1dfa50104289")]
+        public void StoreServiceGuid_IsStore_WhateverTheTitle(string serviceGuid)
+        {
+            Assert.Equal(WindowsUpdateClassifier.Store,
+                WindowsUpdateClassifier.Classify("2026-09 Cumulative Update for Windows 11 (KB5099999)", serviceGuid));
+        }
+
+        [Fact]
+        public void OtherServiceGuid_LeavesTheTitleInCharge()
+        {
+            Assert.Equal(WindowsUpdateClassifier.Os,
+                WindowsUpdateClassifier.Classify("2026-09 Cumulative Update for Windows 11 (KB5099999)", "{7971f918-a847-4430-9279-4a52d1efe18d}"));
+        }
+
+        [Theory]
+        [InlineData("Intel net Driver Update (24.50.0.4)")]
+        [InlineData("PowerShell v7.6.6 (x64)")]
+        [InlineData("Remote help 5.2.1040.0")]
+        [InlineData("Microsoft Edge-Stable Channel Version 140 Update for x64 based Edge-Chromium (Build 140.0.3485.54)")]
+        [InlineData("Microsoft .NET 8.0.20 Security Update for x64 Client (KB5099993)")]
+        [InlineData("Windows Feature Experience Pack 1000.26100.234.0")]
+        [InlineData("KB5099999")]
+        [InlineData("")]
+        [InlineData("   ")]
+        [InlineData(null)]
+        public void EverythingElse_IsOther(string? title)
+        {
+            Assert.Equal(WindowsUpdateClassifier.Other, WindowsUpdateClassifier.Classify(title!, serviceGuid: null));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/WindowsUpdateTrackerTests.cs

@@ -1,6 +1,7 @@
 #nullable enable
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using AutopilotMonitor.Agent.V2.Core.Logging;
 using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
@@ -9,55 +10,81 @@ using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
 using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
 using AutopilotMonitor.DecisionCore.Engine;
 using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.DecisionCore.State;
 using AutopilotMonitor.Shared;
+using Newtonsoft.Json.Linq;
 using Xunit;
 
 namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
 {
     /// <summary>
     /// WindowsUpdateTracker — surfaces quality/cumulative update activity during OOBE from the
-    /// WindowsUpdateClient/Operational channel. Drives the primitive <see cref="WindowsUpdateTracker.ProcessEvent"/>
+    /// WindowsUpdateClient provider: install events from the System log, scan/download events from
+    /// the Operational channel (D-310). Drives the primitive <see cref="WindowsUpdateTracker.ProcessEvent"/>
     /// test seam (no real EventRecord, which is abstract + Windows-only), mirroring the
-    /// ModernDeploymentTracker test pattern.
+    /// ModernDeploymentTracker test pattern. Update titles are the shapes the provider writes.
     /// </summary>
     public sealed class WindowsUpdateTrackerTests : IDisposable
     {
         private static readonly DateTime At = new DateTime(2026, 7, 8, 10, 15, 0, DateTimeKind.Utc);
 
+        private const string Lcu = "2026-09 Cumulative Update for Windows 11, version 25H2 for x64-based Systems (KB5099999)";
+        private const string StoreApp = "9WZDNCRFHVN5-MICROSOFT.WINDOWSCALCULATOR";
+        private const string DefenderIntelligence = "Security Intelligence Update for Microsoft Defender Antivirus - KB2267602 (Version 1.459.505.0) - Current Channel (Broad)";
+
         private readonly TempDirectory _tmp = new TempDirectory();
-        private readonly FakeSignalIngressSink _sink;
-        private readonly WindowsUpdateTracker _tracker;
+        private readonly FakeSignalIngressSink _sink = new FakeSignalIngressSink();
+        private readonly UpdateActivityTally _tally = new UpdateActivityTally();
+        private readonly List<(string Step, string Update, DateTime At)> _osActivity = new List<(string, string, DateTime)>();
+        private readonly WindowsUpdateTracker _system;
+        private readonly WindowsUpdateTracker _operational;
         private long _nextRecordId = 1;
 
         public WindowsUpdateTrackerTests()
         {
-            _sink = new FakeSignalIngressSink();
-            var post = new InformationalEventPost(_sink, new VirtualClock(At));
-            var logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
-            _tracker = new WindowsUpdateTracker(
-                sessionId: "sess-wu",
-                tenantId: "tenant-wu",
-                post: post,
-                logger: logger,
-                backfillEnabled: false,
-                stateDirectory: null); // in-memory dedup for most tests
+            // In-memory dedup for most tests.
+            _system = NewTracker(WindowsUpdateTracker.SystemChannel, stateDirectory: null);
+            _operational = NewTracker(channel: null, stateDirectory: null);
         }
 
         public void Dispose() => _tmp.Dispose();
 
-        private void Emit(int eventId, string? errorCode = null, string? updateTitle = "Cumulative Update KB5099999", long? recordId = null)
+        private WindowsUpdateTracker NewTracker(string? channel, string? stateDirectory) =>
+            new WindowsUpdateTracker(
+                sessionId: "sess-wu",
+                tenantId: "tenant-wu",
+                post: new InformationalEventPost(_sink, new VirtualClock(At)),
+                logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                backfillEnabled: false,
+                stateDirectory: stateDirectory,
+                channel: channel,
+                tally: _tally,
+                onOsUpdateActivity: (step, update, at) => _osActivity.Add((step, update, at)));
+
+        private void Emit(
+            WindowsUpdateTracker tracker,
+            int eventId,
+            string? updateTitle = Lcu,
+            string? errorCode = null,
+            long? recordId = null,
+            string? serviceGuid = null,
+            string? updateCount = null,
+            DateTime? at = null,
+            bool isBackfill = false)
         {
-            _tracker.ProcessEvent(
+            tracker.ProcessEvent(
                 eventId: eventId,
                 level: 4,
                 recordId: recordId ?? _nextRecordId++,
-                timeCreatedUtc: At,
+                timeCreatedUtc: at ?? At,
                 updateTitle: updateTitle,
                 updateGuid: "{8b1c8726-1111-2222-3333-444455556666}",
                 updateRevisionNumber: "200",
                 errorCode: errorCode,
                 formattedDescription: null,
-                isBackfill: false);
+                isBackfill: isBackfill,
+                serviceGuid: serviceGuid,
+                updateCount: updateCount);
         }
 
         private IReadOnlyList<FakeSignalIngressSink.PostedSignal> ByType(string eventType) =>
@@ -70,10 +97,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
         private static IReadOnlyDictionary<string, object> Data(FakeSignalIngressSink.PostedSignal s) =>
             (IReadOnlyDictionary<string, object>)s.TypedPayload!;
 
+        private int Counted(string key) =>
+            _tally.Snapshot().Where(kv => kv.Key == key).Select(kv => kv.Value).SingleOrDefault();
+
+        // ---------------------------------------------------------------------------
+        // Install events (System log)
+        // ---------------------------------------------------------------------------
+
         [Fact]
         public void FailureEvent_EmitsWindowsUpdateFailed_WithDecodedHResult_AndImmediateUpload()
         {
-            Emit(WindowsUpdateTracker.EventId_InstallFailure, errorCode: "0x80240022");
+            Emit(_system, WindowsUpdateTracker.EventId_InstallFailure, errorCode: "0x80240022");
 
             var failed = ByType(Constants.EventTypes.WindowsUpdateFailed);
             var s = Assert.Single(failed);
@@ -83,37 +117,44 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
             var data = Data(s);
             Assert.Equal("0x80240022", data["hresult"]);
             Assert.Equal("WU_E_ALL_UPDATES_FAILED", data["hresultSymbol"]);
-            Assert.Equal("Cumulative Update KB5099999", data["updateTitle"]);
+            Assert.Equal(Lcu, data["updateTitle"]);
             Assert.Equal(20, data["wuEventId"]);
+            Assert.Equal("system", data["wuChannel"]);
+            Assert.Equal("install", data["wuPhase"]);
+            Assert.Equal(WindowsUpdateClassifier.Os, data["updateClass"]);
         }
 
         [Fact]
         public void SuccessEvent_EmitsWindowsUpdateSucceeded_InfoSeverity()
         {
-            Emit(WindowsUpdateTracker.EventId_InstallSuccess);
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess);
 
             var ok = ByType(Constants.EventTypes.WindowsUpdateSucceeded);
             var s = Assert.Single(ok);
             Assert.Equal("Info", s.Payload![SignalPayloadKeys.Severity]);
             Assert.Equal("false", s.Payload![SignalPayloadKeys.ImmediateUpload]);
+            Assert.Equal("installed", Data(s)["wuPhase"]);
         }
 
         [Fact]
-        public void StartedAndDownloadEvents_EmitDebugStarted()
+        public void StartedAndDownloadEvents_EmitInfoStarted_WithTheirPhase()
         {
-            Emit(WindowsUpdateTracker.EventId_InstallStarted);
-            Emit(WindowsUpdateTracker.EventId_DownloadStarted);
+            // Info, not Debug: with only OS updates listed they are the visible progress of a
+            // long OOBE update.
+            Emit(_system, WindowsUpdateTracker.EventId_InstallStarted);
+            Emit(_system, WindowsUpdateTracker.EventId_DownloadStarted);
 
             var started = ByType(Constants.EventTypes.WindowsUpdateStarted);
             Assert.Equal(2, started.Count);
-            Assert.All(started, s => Assert.Equal("Debug", s.Payload![SignalPayloadKeys.Severity]));
+            Assert.All(started, s => Assert.Equal("Info", s.Payload![SignalPayloadKeys.Severity]));
+            Assert.Equal(new[] { "install", "download" }, started.Select(s => (string)Data(s)["wuPhase"]).ToArray());
         }
 
         [Fact]
         public void SameRecordId_ProcessedTwice_EmitsOnce()
         {
-            Emit(WindowsUpdateTracker.EventId_InstallSuccess, recordId: 42);
-            Emit(WindowsUpdateTracker.EventId_InstallSuccess, recordId: 42);
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, recordId: 42);
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, recordId: 42);
 
             Assert.Single(ByType(Constants.EventTypes.WindowsUpdateSucceeded));
         }
@@ -125,8 +166,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
             // with a higher RecordId can be processed first. An older, never-emitted backfill event
             // (lower RecordId) must NOT be suppressed as "already processed" — these early pre-agent
             // OOBE updates are the whole point of the feature. A high-water-mark dedup dropped them.
-            Emit(WindowsUpdateTracker.EventId_InstallSuccess, recordId: 100); // live, high RecordId
-            Emit(WindowsUpdateTracker.EventId_InstallSuccess, recordId: 50);  // backfill, older, never seen
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, recordId: 100); // live, high RecordId
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, recordId: 50);  // backfill, older, never seen
 
             Assert.Equal(2, ByType(Constants.EventTypes.WindowsUpdateSucceeded).Count);
         }
@@ -138,53 +179,212 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
             // time, not at agent start (the ctor's default UtcNow). InformationalEventPost forwards
             // EnrollmentEvent.Timestamp as the signal's OccurredAtUtc, which drives the timeline entry.
             var eventTime = new DateTime(2026, 7, 8, 7, 5, 0, DateTimeKind.Utc); // well before `At`
-            _tracker.ProcessEvent(
-                eventId: WindowsUpdateTracker.EventId_InstallFailure,
-                level: 4,
-                recordId: 7,
-                timeCreatedUtc: eventTime,
-                updateTitle: "KB5099999",
-                updateGuid: null,
-                updateRevisionNumber: null,
-                errorCode: "0x80240022",
-                formattedDescription: null,
-                isBackfill: true);
+            Emit(_system, WindowsUpdateTracker.EventId_InstallFailure, errorCode: "0x80240022",
+                recordId: 7, at: eventTime, isBackfill: true);
 
             var s = Assert.Single(ByType(Constants.EventTypes.WindowsUpdateFailed));
             Assert.Equal(eventTime, s.OccurredAtUtc);
+            Assert.Equal(true, Data(s)["backfilled"]);
         }
 
         [Fact]
         public void NegativeRecordId_IsNeverDeduped()
         {
-            Emit(WindowsUpdateTracker.EventId_InstallSuccess, recordId: -1);
-            Emit(WindowsUpdateTracker.EventId_InstallSuccess, recordId: -1);
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, recordId: -1);
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, recordId: -1);
 
             Assert.Equal(2, ByType(Constants.EventTypes.WindowsUpdateSucceeded).Count);
         }
 
+        // ---------------------------------------------------------------------------
+        // Scan/download events (Operational channel)
+        // ---------------------------------------------------------------------------
+
         [Fact]
-        public void Watermark_PersistsAcrossTrackerInstances()
+        public void Downloaded_EmitsInfoStarted_WithDownloadedPhase()
         {
-            var post = new InformationalEventPost(_sink, new VirtualClock(At));
-            var logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
+            Emit(_operational, WindowsUpdateTracker.EventId_Downloaded);
 
-            var first = new WindowsUpdateTracker("s", "t", post, logger, backfillEnabled: false, stateDirectory: _tmp.Path);
-            first.ProcessEvent(WindowsUpdateTracker.EventId_InstallSuccess, 4, recordId: 500, timeCreatedUtc: At,
-                updateTitle: "KB1", updateGuid: null, updateRevisionNumber: null, errorCode: null,
-                formattedDescription: null, isBackfill: false);
+            var s = Assert.Single(ByType(Constants.EventTypes.WindowsUpdateStarted));
+            Assert.Equal("Info", s.Payload![SignalPayloadKeys.Severity]);
+            Assert.Equal("downloaded", Data(s)["wuPhase"]);
+            Assert.Equal("operational", Data(s)["wuChannel"]);
+        }
 
-            // A fresh tracker (simulating an agent restart) must load the watermark and skip the
-            // already-emitted record when the OOBE backfill re-reads it.
-            var second = new WindowsUpdateTracker("s", "t", post, logger, backfillEnabled: false, stateDirectory: _tmp.Path);
-            second.LoadWatermark();
-            second.ProcessEvent(WindowsUpdateTracker.EventId_InstallSuccess, 4, recordId: 500, timeCreatedUtc: At,
-                updateTitle: "KB1", updateGuid: null, updateRevisionNumber: null, errorCode: null,
-                formattedDescription: null, isBackfill: true);
+        [Fact]
+        public void DownloadFailure_OfAnOsUpdate_EmitsWarning_WithDownloadPhase()
+        {
+            Emit(_operational, WindowsUpdateTracker.EventId_DownloadFailed, errorCode: "0x80248007");
+
+            var s = Assert.Single(ByType(Constants.EventTypes.WindowsUpdateFailed));
+            Assert.Equal("Warning", s.Payload![SignalPayloadKeys.Severity]);
+            Assert.Equal("false", s.Payload![SignalPayloadKeys.ImmediateUpload]);
+            var data = Data(s);
+            Assert.Equal("download", data["wuPhase"]);
+            Assert.Equal("0x80248007", data["hresult"]);
+        }
+
+        [Fact]
+        public void ScanFound_EmitsOnlyChangedCounts_AndCountsTheRepeats()
+        {
+            foreach (var count in new[] { "3", "3", "5", "5", "0" })
+                Emit(_operational, WindowsUpdateTracker.EventId_ScanFound, updateTitle: null, updateCount: count);
+
+            var found = ByType(Constants.EventTypes.WindowsUpdateStarted);
+            Assert.Equal(new[] { "3", "5", "0" }, found.Select(s => (string)Data(s)["updateCount"]).ToArray());
+            Assert.All(found, s => Assert.Equal("Debug", s.Payload![SignalPayloadKeys.Severity]));
+            Assert.All(found, s => Assert.Equal("scan", Data(s)["wuPhase"]));
+            Assert.All(found, s => Assert.False(Data(s).ContainsKey("updateClass")));
+            Assert.Contains("scan found 3 update(s)", found[0].Payload![SignalPayloadKeys.Message]);
+            Assert.Equal(2, Counted("scan_found_repeat"));
+            Assert.Empty(_osActivity); // a scan result is not an update step
+        }
+
+        [Fact]
+        public void ScanFound_IsCappedPerRun()
+        {
+            for (var i = 0; i < WindowsUpdateTracker.MaxScanFoundEmissions + 2; i++)
+                Emit(_operational, WindowsUpdateTracker.EventId_ScanFound, updateTitle: null, updateCount: i.ToString());
+
+            Assert.Equal(WindowsUpdateTracker.MaxScanFoundEmissions, ByType(Constants.EventTypes.WindowsUpdateStarted).Count);
+            Assert.Equal(2, Counted("scan_found_repeat"));
+        }
+
+        [Fact]
+        public void ScanFailed_EmitsEachErrorCodeOnce()
+        {
+            Emit(_operational, WindowsUpdateTracker.EventId_ScanFailed, updateTitle: null, errorCode: "0x8024401c");
+            Emit(_operational, WindowsUpdateTracker.EventId_ScanFailed, updateTitle: null, errorCode: "0x8024401c");
+            Emit(_operational, WindowsUpdateTracker.EventId_ScanFailed, updateTitle: null, errorCode: "0x80072EE2");
+            Emit(_operational, WindowsUpdateTracker.EventId_ScanFailed, updateTitle: null, errorCode: "0x8024401C");
+
+            var failed = ByType(Constants.EventTypes.WindowsUpdateFailed);
+            Assert.Equal(2, failed.Count);
+            Assert.All(failed, s => Assert.Equal("Warning", s.Payload![SignalPayloadKeys.Severity]));
+            Assert.All(failed, s => Assert.Equal("scan", Data(s)["wuPhase"]));
+            Assert.Equal(2, Counted("scan_failed_repeat"));
+            Assert.Empty(_osActivity);
+        }
+
+        [Fact]
+        public void ScanFailed_IsCappedPerRun()
+        {
+            for (var i = 0; i < WindowsUpdateTracker.MaxScanFailedEmissions + 2; i++)
+                Emit(_operational, WindowsUpdateTracker.EventId_ScanFailed, updateTitle: null, errorCode: $"0x8024000{i}");
+
+            Assert.Equal(WindowsUpdateTracker.MaxScanFailedEmissions, ByType(Constants.EventTypes.WindowsUpdateFailed).Count);
+            Assert.Equal(2, Counted("scan_failed_repeat"));
+        }
+
+        // ---------------------------------------------------------------------------
+        // Classification — only OS updates are listed, the rest is counted
+        // ---------------------------------------------------------------------------
+
+        [Theory]
+        [InlineData(StoreApp, null, WindowsUpdateTracker.EventId_InstallSuccess, "store_19")]
+        [InlineData("Some App", "{855e8a7c-ecb4-4ca3-b045-1dfa50104289}", WindowsUpdateTracker.EventId_Downloaded, "store_41")]
+        [InlineData(DefenderIntelligence, null, WindowsUpdateTracker.EventId_InstallStarted, "defender_43")]
+        [InlineData("Intel net Driver Update (24.50.0.4)", null, WindowsUpdateTracker.EventId_DownloadStarted, "other_44")]
+        // A real download failure names no update at all; it must not reach ANALYZE-DEV-004 as
+        // a failed OS update.
+        [InlineData("", null, WindowsUpdateTracker.EventId_DownloadFailed, "other_31")]
+        [InlineData("Some App", "{855e8a7c-ecb4-4ca3-b045-1dfa50104289}", WindowsUpdateTracker.EventId_InstallFailure, "store_20")]
+        public void NonOsUpdates_AreCountedNotEmitted(string title, string? serviceGuid, int eventId, string expectedKey)
+        {
+            var tracker = WindowsUpdateTracker.IsSystemChannelEventId(eventId) ? _system : _operational;
+            Emit(tracker, eventId, updateTitle: title, serviceGuid: serviceGuid, errorCode: "0x80248007");
+
+            Assert.Empty(_sink.Posted);
+            Assert.Empty(_osActivity);
+            Assert.Equal(1, Counted(expectedKey));
+            // The census still sees the channel working.
+            Assert.Equal(1, tracker.EmittedThisRun);
+        }
+
+        [Fact]
+        public void CountedRecord_DeliveredTwice_IsCountedOnce()
+        {
+            // Live watcher and backfill overlap: the seen-set dedups counted records too.
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, updateTitle: StoreApp, recordId: 7);
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, updateTitle: StoreApp, recordId: 7);
+
+            Assert.Equal(1, Counted("store_19"));
+        }
+
+        [Fact]
+        public void OsUpdateSteps_AreReportedToTheEngineCallback()
+        {
+            var t0 = At;
+            Emit(_system, WindowsUpdateTracker.EventId_DownloadStarted, at: t0);
+            Emit(_operational, WindowsUpdateTracker.EventId_Downloaded, at: t0.AddMinutes(4));
+            Emit(_system, WindowsUpdateTracker.EventId_InstallStarted, at: t0.AddMinutes(5));
+            Emit(_system, WindowsUpdateTracker.EventId_InstallSuccess, at: t0.AddMinutes(31));
+            Emit(_system, WindowsUpdateTracker.EventId_InstallFailure, errorCode: "0x800F0922", at: t0.AddMinutes(32));
+            Emit(_operational, WindowsUpdateTracker.EventId_DownloadFailed, errorCode: "0x80248007", at: t0.AddMinutes(33));
+
+            Assert.Equal(
+                new[]
+                {
+                    OsUpdateSteps.DownloadStarted, OsUpdateSteps.Downloaded, OsUpdateSteps.InstallStarted,
+                    OsUpdateSteps.Installed, OsUpdateSteps.Failed, OsUpdateSteps.Failed,
+                },
+                _osActivity.Select(a => a.Step).ToArray());
+            Assert.All(_osActivity, a => Assert.Equal(Lcu, a.Update));
+            Assert.Equal(t0.AddMinutes(31), _osActivity[3].At);
+        }
+
+        [Fact]
+        public void ThrowingCallback_NeverCostsTheEvent()
+        {
+            var tracker = new WindowsUpdateTracker(
+                "s", "t", new InformationalEventPost(_sink, new VirtualClock(At)),
+                new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                backfillEnabled: false,
+                channel: WindowsUpdateTracker.SystemChannel,
+                onOsUpdateActivity: (step, update, at) => throw new InvalidOperationException("boom"));
+
+            Emit(tracker, WindowsUpdateTracker.EventId_InstallSuccess);
 
             Assert.Single(ByType(Constants.EventTypes.WindowsUpdateSucceeded));
         }
 
+        // ---------------------------------------------------------------------------
+        // Channels and XPath
+        // ---------------------------------------------------------------------------
+
+        [Fact]
+        public void DefaultEventIds_FollowTheProviderManifest()
+        {
+            Assert.Equal(WindowsUpdateTracker.SystemChannel, _system.WatchedChannel);
+            Assert.Equal(new[] { 19, 20, 43, 44 }, _system.TargetedEventIds.OrderBy(id => id).ToArray());
+            Assert.Equal(WindowsUpdateTracker.Channel, _operational.WatchedChannel);
+            Assert.Equal(new[] { 25, 26, 31, 41 }, _operational.TargetedEventIds.OrderBy(id => id).ToArray());
+        }
+
+        [Theory]
+        [InlineData(16, true)]
+        [InlineData(19, true)]
+        [InlineData(20, true)]
+        [InlineData(24, true)]
+        [InlineData(27, true)]
+        [InlineData(28, true)]
+        [InlineData(32, true)]
+        [InlineData(33, true)]
+        [InlineData(43, true)]
+        [InlineData(44, true)]
+        [InlineData(212, true)]
+        [InlineData(218, true)]
+        [InlineData(25, false)]
+        [InlineData(26, false)]
+        [InlineData(31, false)]
+        [InlineData(41, false)]
+        [InlineData(15, false)]
+        [InlineData(219, false)]
+        public void IsSystemChannelEventId_MatchesTheManifest(int eventId, bool expected)
+        {
+            Assert.Equal(expected, WindowsUpdateTracker.IsSystemChannelEventId(eventId));
+        }
+
         [Fact]
         public void BuildXPath_ContainsAllTargetedIds_Ordered()
         {
@@ -192,6 +392,113 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
             Assert.Equal("*[System[(EventID=19 or EventID=20 or EventID=43 or EventID=44)]]", xpath);
         }
 
+        [Fact]
+        public void BuildXPath_SharedSystemLog_FiltersTheProvider_AndTheLookback()
+        {
+            // Verified against a real System log: the provider clause keeps the other providers'
+            // EventIDs 19/20/43/44 out of the shared channel.
+            var ids = new HashSet<int> { 44, 19, 20, 43 };
+
+            Assert.Equal(
+                "*[System[Provider[@Name='Microsoft-Windows-WindowsUpdateClient'] and (EventID=19 or EventID=20 or EventID=43 or EventID=44)]]",
+                WindowsUpdateTracker.BuildXPath(ids, WindowsUpdateTracker.ProviderName));
+            Assert.Equal(
+                "*[System[Provider[@Name='Microsoft-Windows-WindowsUpdateClient'] and (EventID=19 or EventID=20 or EventID=43 or EventID=44) and TimeCreated[timediff(@SystemTime) <= 3600000]]]",
+                WindowsUpdateTracker.BuildXPath(ids, WindowsUpdateTracker.ProviderName, lookbackMs: 3600000));
+            Assert.Equal(
+                "*[System[(EventID=25 or EventID=26) and TimeCreated[timediff(@SystemTime) <= 60000]]]",
+                WindowsUpdateTracker.BuildXPath(new HashSet<int> { 26, 25 }, providerName: null, lookbackMs: 60000));
+        }
+
+        // ---------------------------------------------------------------------------
+        // Watermark
+        // ---------------------------------------------------------------------------
+
+        [Fact]
+        public void Watermark_PersistsAcrossTrackerInstances()
+        {
+            var first = NewTracker(WindowsUpdateTracker.SystemChannel, _tmp.Path);
+            Emit(first, WindowsUpdateTracker.EventId_InstallSuccess, recordId: 500);
+
+            // A fresh tracker (simulating an agent restart) must load the watermark and skip the
+            // already-emitted record when the OOBE backfill re-reads it.
+            var second = NewTracker(WindowsUpdateTracker.SystemChannel, _tmp.Path);
+            second.LoadWatermark();
+            Emit(second, WindowsUpdateTracker.EventId_InstallSuccess, recordId: 500, isBackfill: true);
+
+            Assert.Single(ByType(Constants.EventTypes.WindowsUpdateSucceeded));
+        }
+
+        [Fact]
+        public void Watermark_IsPerChannel()
+        {
+            // RecordIds are per channel: System record 500 and Operational record 500 are two
+            // different events and must not dedup each other — before or after a restart.
+            Emit(NewTracker(WindowsUpdateTracker.SystemChannel, _tmp.Path), WindowsUpdateTracker.EventId_InstallSuccess, recordId: 500);
+            Emit(NewTracker(null, _tmp.Path), WindowsUpdateTracker.EventId_Downloaded, recordId: 500);
+
+            Assert.Single(ByType(Constants.EventTypes.WindowsUpdateSucceeded));
+            Assert.Single(ByType(Constants.EventTypes.WindowsUpdateStarted));
+            Assert.Equal(500L, ReadWatermark(WindowsUpdateTracker.SystemWatermarkStateFileName));
+            Assert.Equal(500L, ReadWatermark(WindowsUpdateTracker.WatermarkStateFileName));
+
+            var system = NewTracker(WindowsUpdateTracker.SystemChannel, _tmp.Path);
+            var operational = NewTracker(null, _tmp.Path);
+            system.LoadWatermark();
+            operational.LoadWatermark();
+            Emit(system, WindowsUpdateTracker.EventId_InstallSuccess, recordId: 500, isBackfill: true);
+            Emit(operational, WindowsUpdateTracker.EventId_Downloaded, recordId: 500, isBackfill: true);
+
+            Assert.Single(ByType(Constants.EventTypes.WindowsUpdateSucceeded));
+            Assert.Single(ByType(Constants.EventTypes.WindowsUpdateStarted));
+        }
+
+        [Fact]
+        public void CountedRecords_WriteNoStateFile()
+        {
+            // A Store/Defender burst must not cost a state-file write per record; only emitted
+            // records move the persisted watermark.
+            var tracker = NewTracker(WindowsUpdateTracker.SystemChannel, _tmp.Path);
+            Emit(tracker, WindowsUpdateTracker.EventId_InstallSuccess, updateTitle: StoreApp, recordId: 600);
+            Emit(tracker, WindowsUpdateTracker.EventId_InstallStarted, updateTitle: DefenderIntelligence, recordId: 601);
+
+            Assert.False(File.Exists(Path.Combine(_tmp.Path, WindowsUpdateTracker.SystemWatermarkStateFileName)));
+
+            Emit(tracker, WindowsUpdateTracker.EventId_InstallStarted, recordId: 602);
+            Assert.Equal(602L, ReadWatermark(WindowsUpdateTracker.SystemWatermarkStateFileName));
+        }
+
+        [Fact]
+        public void Watermark_PersistsOnlyAfterTheEngineSignalWasHandedOver()
+        {
+            // A restart's backfill skips a persisted record, so the record's engine signal must be
+            // on its way before the watermark reaches the disk — never the other way round.
+            var path = Path.Combine(_tmp.Path, WindowsUpdateTracker.SystemWatermarkStateFileName);
+            bool? watermarkOnDiskAtSignal = null;
+            var tracker = new WindowsUpdateTracker(
+                sessionId: "sess-wu",
+                tenantId: "tenant-wu",
+                post: new InformationalEventPost(_sink, new VirtualClock(At)),
+                logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                backfillEnabled: false,
+                stateDirectory: _tmp.Path,
+                channel: WindowsUpdateTracker.SystemChannel,
+                tally: _tally,
+                onOsUpdateActivity: (step, update, at) => watermarkOnDiskAtSignal = File.Exists(path));
+
+            Emit(tracker, WindowsUpdateTracker.EventId_InstallStarted, recordId: 700);
+
+            Assert.False(watermarkOnDiskAtSignal);
+            Assert.Equal(700L, ReadWatermark(WindowsUpdateTracker.SystemWatermarkStateFileName));
+        }
+
+        private long ReadWatermark(string fileName) =>
+            JObject.Parse(File.ReadAllText(Path.Combine(_tmp.Path, fileName)))["LastRecordId"]!.Value<long>();
+
+        // ---------------------------------------------------------------------------
+        // Parsing and HRESULT decoding
+        // ---------------------------------------------------------------------------
+
         [Fact]
         public void ParseEventData_ExtractsNamedFields_NamespaceAgnostic()
         {
@@ -212,6 +519,24 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
             Assert.True(data.ContainsKey("UPDATETITLE"));
         }
 
+        [Fact]
+        public void ParseEventData_ReadsTheScanFields()
+        {
+            // Event 26 (scan found N) and 25 (scan failed) carry no update title.
+            const string xml =
+                "<Event xmlns='http://schemas.microsoft.com/win/2004/08/events/event'>" +
+                "<System><EventID>26</EventID></System>" +
+                "<EventData>" +
+                "<Data Name='updateCount'>3</Data>" +
+                "<Data Name='serviceGuid'>{8b24b027-1dee-babb-9a95-3517dfb9c552}</Data>" +
+                "</EventData></Event>";
+
+            var data = WindowsUpdateTracker.ParseEventData(xml);
+            Assert.Equal("3", data["updateCount"]);
+            Assert.Equal("{8b24b027-1dee-babb-9a95-3517dfb9c552}", data["serviceGuid"]);
+            Assert.False(data.ContainsKey("updateTitle"));
+        }
+
         [Fact]
         public void ParseEventData_MalformedXml_ReturnsEmpty_NeverThrows()
         {
@@ -303,10 +628,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
             var data = Data(s);
             Assert.Equal("21=1,25=3", data["wuClientCensus"]);
             Assert.Equal("200=2", data["updateOrchestratorCensus"]);
-            Assert.Equal("19,20,43,44", data["targetedEventIds"]);
+            Assert.Equal("25,26,31,41", data["targetedEventIds"]);
             Assert.False(data.ContainsKey("censusTruncated"));
         }
 
+        [Fact]
+        public void Census_ListsTheTargetedIdsOfEveryChannel()
+        {
+            // The host runs the census on the Operational instance; the evidence must still say
+            // the System-log install IDs were watched too.
+            var tracker = BuildCensusTracker(censusEnabled: true, osBuildChanged: true);
+
+            tracker.EmitChannelCensusIfBlind(otherChannelsEmitted: 0, otherTargetedEventIds: new[] { 44, 19, 20, 43 });
+
+            var s = Assert.Single(ByType(Constants.EventTypes.WindowsUpdateChannelCensus));
+            Assert.Equal("19,20,25,26,31,41,43,44", Data(s)["targetedEventIds"]);
+        }
+
         [Fact]
         public void Census_BuildUnchanged_EmitsNothing()
         {
@@ -320,17 +658,27 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
         [Fact]
         public void Census_TargetedEventsWereEmittedThisRun_EmitsNothing()
         {
-            // The watcher captured the update through its normal path — no blind spot to report.
+            // The watcher captured activity through its normal path — no blind spot to report.
+            // Any class counts: a counted Store update proves the channel is read as well.
             var tracker = BuildCensusTracker(censusEnabled: true, osBuildChanged: true);
-            tracker.ProcessEvent(WindowsUpdateTracker.EventId_InstallSuccess, 4, recordId: 9, timeCreatedUtc: At,
-                updateTitle: "KB1", updateGuid: null, updateRevisionNumber: null, errorCode: null,
-                formattedDescription: null, isBackfill: false);
+            Emit(tracker, WindowsUpdateTracker.EventId_Downloaded, updateTitle: StoreApp, recordId: 9);
 
             tracker.EmitChannelCensusIfBlind();
 
             Assert.Empty(ByType(Constants.EventTypes.WindowsUpdateChannelCensus));
         }
 
+        [Fact]
+        public void Census_AnotherChannelEmitted_EmitsNothing()
+        {
+            // The System-log watcher saw the install — the update was not missed.
+            var tracker = BuildCensusTracker(censusEnabled: true, osBuildChanged: true);
+
+            tracker.EmitChannelCensusIfBlind(otherChannelsEmitted: 1);
+
+            Assert.Empty(ByType(Constants.EventTypes.WindowsUpdateChannelCensus));
+        }
+
         [Fact]
         public void Census_DisabledByConfig_EmitsNothing()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Transport/EmergencyReporterTests.cs

@@ -20,6 +20,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Transport
         private sealed class FakeApiClient : BackendApiClient
         {
             public readonly List<TimeSpan?> Timeouts = new List<TimeSpan?>();
+            public readonly List<AgentErrorReport> Reports = new List<AgentErrorReport>();
             public readonly Queue<bool> Results = new Queue<bool>();
 
             public FakeApiClient() : base(
@@ -40,6 +41,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Transport
             public override Task<bool> ReportAgentErrorAsync(AgentErrorReport report, TimeSpan? timeout = null)
             {
                 Timeouts.Add(timeout);
+                Reports.Add(report);
                 return Task.FromResult(Results.Count > 0 && Results.Dequeue());
             }
         }
@@ -139,5 +141,37 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Transport
 
             Assert.Equal(2, client.Calls);
         }
+
+        [Fact]
+        public async Task Session_age_is_carried_in_the_report_and_absent_by_default()
+        {
+            // One reporter per report: a delivered report starts the 10-minute cooldown.
+            var client = new FakeApiClient();
+            client.Results.Enqueue(true);
+            client.Results.Enqueue(true);
+
+            await Reporter(client).TrySendAsync(AgentErrorType.SessionAgeEmergencyBreak, "m", sessionAgeHours: 478.2);
+            await Reporter(client).TrySendAsync(AgentErrorType.ConfigFetchFailed, "m");
+
+            Assert.Equal(2, client.Reports.Count);
+            Assert.Equal(478.2, client.Reports[0].SessionAgeHours);
+            Assert.Null(client.Reports[1].SessionAgeHours);
+        }
+
+        [Fact]
+        public async Task Prior_registration_failure_is_carried_in_the_report_and_absent_by_default()
+        {
+            var client = new FakeApiClient();
+            client.Results.Enqueue(true);
+            client.Results.Enqueue(true);
+            var record = new RegistrationFailureSummary { FailedRuns = 2, Outcome = "Failed", NetworkLinkUpAtEnd = false };
+
+            await Reporter(client).TrySendAsync(AgentErrorType.SessionAgeEmergencyBreak, "m", priorRegistrationFailure: record);
+            await Reporter(client).TrySendAsync(AgentErrorType.ConfigFetchFailed, "m");
+
+            Assert.Equal(2, client.Reports.Count);
+            Assert.Same(record, client.Reports[0].PriorRegistrationFailure);
+            Assert.Null(client.Reports[1].PriorRegistrationFailure);
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Orchestration/DecisionStepProcessorTerminalStageTests.cs

@@ -153,6 +153,62 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
             Assert.Equal(0, callCount);
         }
 
+        [Fact]
+        public void Stopped_waiting_fires_callback_once_with_the_stage_still_non_terminal()
+        {
+            // D-310: the engine stopped waiting for the user without a verdict. The stage stays
+            // non-terminal, yet the agent must end the session — the callback carries the state.
+            using var rig = new Rig();
+            DecisionState? captured = null;
+            var callCount = 0;
+            var sut = rig.Build(DecisionState.CreateInitial("S1", "T1"),
+                onTerminal: state =>
+                {
+                    Interlocked.Increment(ref callCount);
+                    captured = state;
+                });
+
+            var builder = new DecisionStateBuilder(sut.CurrentState)
+            {
+                Stage = SessionStage.EspAccountSetup,
+                StepIndex = sut.CurrentState.StepIndex + 1,
+                StoppedWaitingReason = new SignalFact<string>(StoppedWaitingReasons.OobeUpdateNoSignIn, 1),
+            };
+            var stopped = builder.Build();
+            var step = new DecisionStep(stopped, new DecisionTransition(
+                stepIndex: stopped.StepIndex, sessionTraceOrdinal: 1, signalOrdinalRef: 1, occurredAtUtc: At,
+                trigger: "DeadlineFired:advisory_completion:OobeUpdateSignInWaitExpired",
+                fromStage: SessionStage.SessionStarted, toStage: SessionStage.EspAccountSetup,
+                taken: true, deadEndReason: null, reducerVersion: "2.0.0.0"), Array.Empty<DecisionEffect>());
+            sut.ApplyStep(step, Sig(1, At));
+
+            // A follow-up step must not fire it again.
+            sut.ApplyStep(StepToStage(sut.CurrentState, SessionStage.EspAccountSetup, signalOrdinal: 2, at: At.AddSeconds(1)),
+                Sig(2, At.AddSeconds(1)));
+
+            Assert.Equal(1, callCount);
+            Assert.Equal(SessionStage.EspAccountSetup, captured!.Stage);
+            Assert.Equal(StoppedWaitingReasons.OobeUpdateNoSignIn, captured.StoppedWaitingReason!.Value);
+        }
+
+        [Fact]
+        public void Stopped_waiting_on_load_does_not_refire_the_callback()
+        {
+            // The orchestrator ends a recovered stopped-waiting session itself at start.
+            using var rig = new Rig();
+            var callCount = 0;
+            var recovered = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1"))
+            {
+                Stage = SessionStage.EspAccountSetup,
+                StoppedWaitingReason = new SignalFact<string>(StoppedWaitingReasons.OobeUpdateNoSignIn, 7),
+            }.Build();
+
+            var sut = rig.Build(recovered, onTerminal: _ => Interlocked.Increment(ref callCount));
+            sut.ApplyStep(StepToStage(sut.CurrentState, SessionStage.EspAccountSetup, signalOrdinal: 8, at: At), Sig(8, At));
+
+            Assert.Equal(0, callCount);
+        }
+
         [Fact]
         public void Terminal_callback_null_is_supported()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Orchestration/DefaultComponentFactoryGatherStateTests.cs

@@ -0,0 +1,103 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using AutopilotMonitor.Agent.V2.Core.Configuration;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
+{
+    /// <summary>
+    /// The production factory hands its state directory to the gather executor. Without it every
+    /// unit test of the gather state passes while the agent keeps replaying logs after each reboot —
+    /// the one line in <see cref="DefaultComponentFactory"/> is the whole feature.
+    /// </summary>
+    [Collection("SerialThreading")] // the startup rule executes on the shared ThreadPool
+    public sealed class DefaultComponentFactoryGatherStateTests : IDisposable
+    {
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly TempDirectory _stateDir = new TempDirectory();
+
+        // %TEMP% lives under C:\Users (hard-blocked) — the log sits beside the test assembly.
+        private readonly string _logDir = Path.Combine(
+            AppContext.BaseDirectory, "factory-gather-state-" + Guid.NewGuid().ToString("N"));
+
+        public DefaultComponentFactoryGatherStateTests() => Directory.CreateDirectory(_logDir);
+
+        public void Dispose()
+        {
+            _tmp.Dispose();
+            _stateDir.Dispose();
+            try { Directory.Delete(_logDir, recursive: true); } catch { /* best effort */ }
+        }
+
+        [Fact]
+        public void Gather_host_built_by_the_factory_persists_logparser_positions_in_the_state_directory()
+        {
+            var log = Path.Combine(_logDir, "vendor.log");
+            File.WriteAllText(log, "Update one\n");
+
+            var factory = new DefaultComponentFactory(
+                agentConfig: new AgentConfiguration
+                {
+                    ApiBaseUrl = "https://example",
+                    TenantId = "t",
+                    SessionId = "s",
+                    UnrestrictedMode = true,
+                },
+                remoteConfig: new AgentConfigResponse
+                {
+                    Collectors = CollectorConfiguration.CreateDefault(),
+                    GatherRules = new List<GatherRule>
+                    {
+                        new GatherRule
+                        {
+                            RuleId = "vendor-log",
+                            Title = "vendor log",
+                            CollectorType = "logparser",
+                            Target = log,
+                            Parameters = new Dictionary<string, string> { ["pattern"] = "^Update", ["format"] = "text" },
+                            Trigger = "startup",
+                            OutputEventType = "vendor_update",
+                            Enabled = true,
+                        },
+                    },
+                },
+                networkMetrics: null,
+                agentVersion: "test",
+                stateDirectory: _stateDir.Path,
+                startupEventGate: null);
+
+            var hosts = factory.CreateCollectorHosts(
+                sessionId: "s",
+                tenantId: "t",
+                logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                whiteGloveSealingPatternIds: Array.Empty<string>(),
+                ingress: new FakeSignalIngressSink(),
+                clock: new VirtualClock(new DateTime(2026, 9, 28, 12, 0, 0, DateTimeKind.Utc)),
+                telemetrySpool: null,
+                timelineEvents: null).Hosts;
+            try
+            {
+                hosts.OfType<GatherRuleExecutorHost>().Single().Start();
+
+                var stateFile = Path.Combine(_stateDir.Path, GatherRuleStatePersistence.FileName);
+                Assert.True(SpinWait.SpinUntil(() => File.Exists(stateFile), TimeSpan.FromSeconds(10)),
+                    "the gather host did not write its state into the factory's state directory");
+            }
+            finally
+            {
+                foreach (var host in hosts)
+                {
+                    try { host.Dispose(); } catch { /* best-effort cleanup */ }
+                }
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Orchestration/GatherRuleExecutorHostTimelineFeedTests.cs

@@ -16,7 +16,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
     /// <summary>
     /// GatherRuleExecutorHost feeds its phase_change / phase_exit / on_event triggers from the
     /// POST-REDUCE <see cref="TimelineEventStream"/> (emitted timeline events), not from raw
-    /// signals. Regression anchor: session 32312a32 (rsneuffen.de) — a phase_change rule on
+    /// signals. Regression anchor: session 32312a32 — a phase_change rule on
     /// FinalizingSetup fired at the raw EspPhaseChanged(FinalizingSetup) signal (ESP exit),
     /// 7 minutes before the engine's RealmJoin-gated phase_transition(FinalizingSetup), and read
     /// a registry key before the RealmJoin package wrote it. With the timeline feed the rule

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Orchestration/RecoveryCoordinatorTests.cs

@@ -162,6 +162,28 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
             Assert.Equal(SessionStage.AwaitingHello, result.InitialState.Stage);
         }
 
+        [Fact]
+        public void Clean_snapshot_of_a_rotated_session_adopts_the_current_session_id()
+        {
+            // SESSION-OWNER-BINDING: the backend refused the persisted session id at registration,
+            // the agent rotated, and the snapshot on disk still names the old session. The
+            // enrollment state carries over; the session id must be the current one.
+            using var rig = new Rig();
+            var saved = DecisionState.CreateInitial("S-REFUSED", TenantId)
+                .ToBuilder()
+                .WithStage(SessionStage.EspAccountSetup)
+                .WithStepIndex(7)
+                .WithLastAppliedSignalOrdinal(6)
+                .Build();
+            SeedSnapshot(rig, saved);
+
+            var result = rig.Recover();
+
+            Assert.Equal(SessionId, result.InitialState.SessionId);
+            Assert.Equal(SessionStage.EspAccountSetup, result.InitialState.Stage);
+            Assert.Equal(7, result.InitialState.StepIndex);
+        }
+
         [Fact]
         public void Snapshot_plus_pending_tail_replays_tail_onto_snapshot()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Orchestration/RecoveryPathTests.cs

@@ -174,6 +174,40 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
             sut.Stop();
         }
 
+        [Fact]
+        public void Recovered_stopped_waiting_state_ends_the_session_at_start()
+        {
+            // D-310: a crash between "the engine stopped waiting" and the termination must not
+            // leave the session running — the restart ends it the same way, with the engine's reason.
+            using var rig = new Rig();
+            Directory.CreateDirectory(rig.StateDir);
+
+            var stoppedState = DecisionState.CreateInitial("S1", "T1")
+                .ToBuilder()
+                .WithStage(SessionStage.EspAccountSetup)
+                .WithStepIndex(9)
+                .Build()
+                .ToBuilder();
+            stoppedState.StoppedWaitingReason = new SignalFact<string>(StoppedWaitingReasons.OobeUpdateNoSignIn, 42);
+            new SnapshotPersistence(Path.Combine(rig.StateDir, "snapshot.json")).Save(stoppedState.Build());
+
+            var sut = rig.Build();
+            using var fired = new ManualResetEventSlim(false);
+            EnrollmentTerminatedEventArgs? captured = null;
+            sut.Terminated += (_, e) => { captured = e; fired.Set(); };
+
+            sut.Start();
+            Assert.True(fired.Wait(5000), "Terminated did not fire for the recovered stopped-waiting state.");
+
+            Assert.Equal(EnrollmentTerminationReason.StoppedWaiting, captured!.Reason);
+            Assert.Equal(EnrollmentTerminationOutcome.TimedOut, captured.Outcome);
+            Assert.Equal(StoppedWaitingReasons.OobeUpdateNoSignIn, captured.StopReason);
+            Assert.Equal(SessionStage.EspAccountSetup.ToString(), captured.StageName);
+            Assert.Contains("60 minutes", captured.Details);
+
+            sut.Stop();
+        }
+
         // ================================================================= Sonderfall 2: Segment-Quarantine
 
         [Fact]

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Orchestration/WindowsUpdateWatcherHostTests.cs

@@ -0,0 +1,209 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.DecisionCore.State;
+using AutopilotMonitor.Shared;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
+{
+    /// <summary>
+    /// WindowsUpdateWatcherHost (D-310) — routes every configured WU EventID to the channel the
+    /// provider manifest writes it to, reports counted activity once, and feeds Windows/.NET update
+    /// steps to the decision engine unless <c>OobeUpdatePhaseMode</c> is Off. The event-log
+    /// watchers themselves are not armed here; the trackers' ProcessEvent seams drive the host.
+    /// </summary>
+    public sealed class WindowsUpdateWatcherHostTests : IDisposable
+    {
+        private static readonly DateTime At = new DateTime(2026, 10, 1, 9, 30, 0, DateTimeKind.Utc);
+        private const string Lcu = "2026-09 Cumulative Update for Windows 11, version 25H2 for x64-based Systems (KB5099999)";
+
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly FakeSignalIngressSink _sink = new FakeSignalIngressSink();
+        private long _nextRecordId = 1;
+
+        public void Dispose() => _tmp.Dispose();
+
+        private WindowsUpdateWatcherHost Build(bool osUpdateSignalsEnabled, bool servicingWatcherEnabled = true) =>
+            new WindowsUpdateWatcherHost(
+                sessionId: "sess-wuhost",
+                tenantId: "tenant-wuhost",
+                logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                ingress: _sink,
+                clock: new VirtualClock(At),
+                targetedEventIds: new[] { 19, 20, 43, 44 },
+                backfillLookbackMinutes: 0,
+                stateDirectory: _tmp.Path,
+                operationalEventIds: new[] { 25, 26, 31, 41 },
+                servicingWatcherEnabled: servicingWatcherEnabled,
+                osUpdateSignalsEnabled: osUpdateSignalsEnabled);
+
+        private void Wu(WindowsUpdateTracker tracker, int eventId, string title, DateTime at) =>
+            tracker.ProcessEvent(eventId, 4, _nextRecordId++, at, title, updateGuid: null, updateRevisionNumber: null,
+                errorCode: null, formattedDescription: null, isBackfill: false);
+
+        private void Cbs(ServicingTracker tracker, int eventId, string client, DateTime at) =>
+            tracker.ProcessEvent(eventId, _nextRecordId++, at, "KB5099999", initialState: null, targetState: "Installed",
+                errorCode: "0x0", client: client, isBackfill: false);
+
+        private IReadOnlyList<FakeSignalIngressSink.PostedSignal> OsUpdateActivity() =>
+            _sink.Posted.Where(p => p.Kind == DecisionSignalKind.OsUpdateActivity).ToList();
+
+        private IReadOnlyList<FakeSignalIngressSink.PostedSignal> ByType(string eventType) =>
+            _sink.Posted.Where(p =>
+                p.Kind == DecisionSignalKind.InformationalEvent
+                && p.Payload != null
+                && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                && et == eventType).ToList();
+
+        // ---------------------------------------------------------------- routing ----
+
+        [Fact]
+        public void RouteEventIds_Defaults_SplitByManifest()
+        {
+            var (system, operational) = WindowsUpdateWatcherHost.RouteEventIds(new[] { 19, 20, 43, 44 }, new[] { 25, 26, 31, 41 });
+
+            Assert.Equal(new[] { 19, 20, 43, 44 }, system);
+            Assert.Equal(new[] { 25, 26, 31, 41 }, operational);
+        }
+
+        [Fact]
+        public void RouteEventIds_MisplacedIds_EndUpOnTheirRealChannel()
+        {
+            // An old config that lists 41 under the targeted IDs, or 20 under the operational
+            // ones, must still watch the channel that carries them.
+            var (system, operational) = WindowsUpdateWatcherHost.RouteEventIds(new[] { 41, 19 }, new[] { 20, 41 });
+
+            Assert.Equal(new[] { 19, 20 }, system);
+            Assert.Equal(new[] { 41 }, operational);
+        }
+
+        [Fact]
+        public void RouteEventIds_NothingConfigured_WatchesNothing()
+        {
+            var (system, operational) = WindowsUpdateWatcherHost.RouteEventIds(null, Array.Empty<int>());
+
+            Assert.Empty(system);
+            Assert.Empty(operational);
+        }
+
+        [Fact]
+        public void Host_BuildsOneTrackerPerChannel_AndTheServicingTracker()
+        {
+            var host = Build(osUpdateSignalsEnabled: false);
+
+            Assert.Equal(WindowsUpdateTracker.SystemChannel, host.SystemTrackerForTest!.WatchedChannel);
+            Assert.Equal(new[] { 19, 20, 43, 44 }, host.SystemTrackerForTest.TargetedEventIds.OrderBy(id => id).ToArray());
+            Assert.Equal(WindowsUpdateTracker.Channel, host.OperationalTrackerForTest!.WatchedChannel);
+            Assert.Equal(new[] { 25, 26, 31, 41 }, host.OperationalTrackerForTest.TargetedEventIds.OrderBy(id => id).ToArray());
+            Assert.NotNull(host.ServicingTrackerForTest);
+        }
+
+        [Fact]
+        public void ServicingWatcherDisabled_BuildsNoServicingTracker()
+        {
+            Assert.Null(Build(osUpdateSignalsEnabled: false, servicingWatcherEnabled: false).ServicingTrackerForTest);
+        }
+
+        // ------------------------------------------------- engine signal behind flag ----
+
+        [Fact]
+        public void OsUpdateSignalsDisabled_ListsTheUpdate_ButPostsNoEngineSignal()
+        {
+            var host = Build(osUpdateSignalsEnabled: false);
+
+            Wu(host.SystemTrackerForTest!, WindowsUpdateTracker.EventId_InstallStarted, Lcu, At);
+            Cbs(host.ServicingTrackerForTest!, ServicingTracker.EventId_RebootRequired, "UpdateAgentLCU", At.AddMinutes(20));
+
+            Assert.Single(ByType(Constants.EventTypes.WindowsUpdateStarted));
+            Assert.Single(ByType(Constants.EventTypes.WindowsUpdateServicing));
+            Assert.Empty(OsUpdateActivity());
+        }
+
+        [Fact]
+        public void OsUpdateSignalsEnabled_PostsOsUpdateActivity_FromBothSources()
+        {
+            var host = Build(osUpdateSignalsEnabled: true);
+            var wuAt = DateTime.SpecifyKind(At, DateTimeKind.Unspecified);
+
+            Wu(host.SystemTrackerForTest!, WindowsUpdateTracker.EventId_InstallStarted, Lcu, wuAt);
+            Cbs(host.ServicingTrackerForTest!, ServicingTracker.EventId_RebootRequired, "UpdateAgentLCU", At.AddMinutes(20));
+
+            var signals = OsUpdateActivity();
+            Assert.Equal(2, signals.Count);
+
+            var wu = signals[0];
+            Assert.Equal(OsUpdateSteps.InstallStarted, wu.Payload![OsUpdatePayloadKeys.Step]);
+            Assert.Equal("wu", wu.Payload![OsUpdatePayloadKeys.Source]);
+            Assert.Equal(Lcu, wu.Payload![OsUpdatePayloadKeys.Update]);
+            Assert.Equal("WindowsUpdateWatcher", wu.SourceOrigin);
+            Assert.Equal(EvidenceKind.Raw, wu.Evidence.Kind);
+            Assert.Equal("os-update-activity:wu", wu.Evidence.Identifier);
+            Assert.Equal(At, wu.OccurredAtUtc);
+            Assert.Equal(DateTimeKind.Utc, wu.OccurredAtUtc.Kind);
+            Assert.Equal(1, wu.KindSchemaVersion);
+
+            var cbs = signals[1];
+            Assert.Equal(OsUpdateSteps.RebootRequired, cbs.Payload![OsUpdatePayloadKeys.Step]);
+            Assert.Equal("servicing", cbs.Payload![OsUpdatePayloadKeys.Source]);
+            Assert.Equal("KB5099999", cbs.Payload![OsUpdatePayloadKeys.Update]);
+            Assert.Equal("ServicingWatcher", cbs.SourceOrigin);
+            Assert.Equal("os-update-activity:servicing", cbs.Evidence.Identifier);
+            Assert.Equal(At.AddMinutes(20), cbs.OccurredAtUtc);
+        }
+
+        [Fact]
+        public void OsUpdateSignalsEnabled_NonOsActivity_NeverReachesTheEngine()
+        {
+            var host = Build(osUpdateSignalsEnabled: true);
+
+            Wu(host.SystemTrackerForTest!, WindowsUpdateTracker.EventId_InstallSuccess, "9NSTH9KHZDLQ-Microsoft.UI.Xaml.2.8", At);
+            Wu(host.OperationalTrackerForTest!, WindowsUpdateTracker.EventId_Downloaded,
+                "Security Intelligence Update for Microsoft Defender Antivirus - KB2267602 (Version 1.459.505.0) - Current Channel (Broad)", At);
+            Cbs(host.ServicingTrackerForTest!, ServicingTracker.EventId_StateReached, "CbsTask", At);
+
+            Assert.Empty(OsUpdateActivity());
+            Assert.Empty(_sink.Posted);
+        }
+
+        // ------------------------------------------------------- activity summary ----
+
+        [Fact]
+        public void ActivitySummary_IsEmittedOnce_WhenTheHostStops()
+        {
+            var host = Build(osUpdateSignalsEnabled: false);
+            Wu(host.SystemTrackerForTest!, WindowsUpdateTracker.EventId_InstallSuccess, "9NSTH9KHZDLQ-Microsoft.UI.Xaml.2.8", At);
+            Wu(host.SystemTrackerForTest!, WindowsUpdateTracker.EventId_InstallSuccess, "9NBLGGH4NNS1-Microsoft.DesktopAppInstaller", At);
+            Cbs(host.ServicingTrackerForTest!, ServicingTracker.EventId_InitiatingChanges, "CbsTask", At);
+
+            // The termination path stops the host explicitly and disposes it afterwards.
+            host.Stop();
+            host.Dispose();
+
+            var summary = Assert.Single(ByType(Constants.EventTypes.WindowsUpdateActivitySummary));
+            Assert.Equal("Debug", summary.Payload![SignalPayloadKeys.Severity]);
+            Assert.Contains("3 event(s)", summary.Payload![SignalPayloadKeys.Message]);
+            var data = (IReadOnlyDictionary<string, object>)summary.TypedPayload!;
+            Assert.Equal(2, data["store_19"]);
+            Assert.Equal(1, data["servicing_other_1"]);
+        }
+
+        [Fact]
+        public void ActivitySummary_NothingCounted_EmitsNothing()
+        {
+            var host = Build(osUpdateSignalsEnabled: false);
+            Wu(host.SystemTrackerForTest!, WindowsUpdateTracker.EventId_InstallSuccess, Lcu, At);
+
+            host.Stop();
+
+            Assert.Empty(ByType(Constants.EventTypes.WindowsUpdateActivitySummary));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Program/BackendSessionRegistrationTests.cs

@@ -118,5 +118,88 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Program
             Assert.Throws<ArgumentNullException>(
                 () => BackendSessionRegistration.Register(config, auth, http, "1.0", consoleMode: false, logger: null));
         }
+
+        // ============================================================ failed-registration record
+
+        [Fact]
+        public void RecordRegistrationRun_records_a_failed_run_with_its_window_and_bounded_error()
+        {
+            using var tmp = new TempDirectory();
+            var persistence = new SessionIdPersistence(tmp.Path);
+            var started = new DateTime(2026, 8, 20, 9, 0, 0, DateTimeKind.Utc);
+
+            BackendSessionRegistration.RecordRegistrationRun(
+                persistence, SessionRegistrationResult.Failed(new string('e', 1000)),
+                started, started.AddSeconds(1204.46), linkUpAtStart: false, linkUpAtEnd: true,
+                configFetchOutcome: "UsedDefaults", logger: NewLogger(tmp.Path));
+
+            var record = persistence.LoadRegistrationFailure();
+            Assert.NotNull(record);
+            Assert.Equal(1, record!.FailedRuns);
+            Assert.Equal("Failed", record.Outcome);
+            Assert.Equal(BackendSessionRegistration.MaxRecordedErrorLength, record.LastError!.Length);
+            Assert.False(record.NetworkLinkUpAtStart);
+            Assert.True(record.NetworkLinkUpAtEnd);
+            Assert.Equal(1204.5, record.AttemptWindowSeconds);
+            Assert.Equal("UsedDefaults", record.ConfigFetchOutcome);
+            Assert.Equal(started.AddSeconds(1204.46), record.LastFailedAtUtc);
+        }
+
+        [Fact]
+        public void RecordRegistrationRun_records_auth_failures_and_clears_on_success()
+        {
+            using var tmp = new TempDirectory();
+            var persistence = new SessionIdPersistence(tmp.Path);
+            var at = new DateTime(2026, 8, 20, 9, 0, 0, DateTimeKind.Utc);
+
+            BackendSessionRegistration.RecordRegistrationRun(
+                persistence, SessionRegistrationResult.AuthFailed(401, "unauthorized"),
+                at, at.AddSeconds(3), true, true, "Succeeded", NewLogger(tmp.Path));
+            Assert.Equal("AuthFailed", persistence.LoadRegistrationFailure()!.Outcome);
+
+            BackendSessionRegistration.RecordRegistrationRun(
+                persistence, SessionRegistrationResult.Succeeded(new RegisterSessionResponse { Success = true }),
+                at, at.AddSeconds(1), true, true, "Succeeded", NewLogger(tmp.Path));
+            Assert.Null(persistence.LoadRegistrationFailure());
+        }
+
+        [Fact]
+        public void RecordRegistrationRun_without_persistence_is_a_no_op()
+        {
+            using var tmp = new TempDirectory();
+            BackendSessionRegistration.RecordRegistrationRun(
+                null, SessionRegistrationResult.Failed("x"), DateTime.UtcNow, DateTime.UtcNow,
+                null, null, null, NewLogger(tmp.Path));
+        }
+
+        // ============================================================ emergency-break message
+
+        [Fact]
+        public void Break_message_names_failed_registrations_in_invariant_culture()
+        {
+            var previous = System.Threading.Thread.CurrentThread.CurrentCulture;
+            try
+            {
+                System.Threading.Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo("de-DE");
+                var record = new RegistrationFailureSummary { FailedRuns = 3, Outcome = "Failed", NetworkLinkUpAtEnd = false };
+
+                var message = EmergencyBreakReporter.BuildMessage(478.2, 48, record);
+
+                Assert.Contains("session age 478.2h (cap 48h)", message);
+                Assert.EndsWith(" 3 earlier start(s) failed to register (last: Failed, network link at end: down).", message);
+            }
+            finally
+            {
+                System.Threading.Thread.CurrentThread.CurrentCulture = previous;
+            }
+        }
+
+        [Fact]
+        public void Break_message_without_record_keeps_the_historical_text()
+        {
+            Assert.Equal(
+                "Agent absolute session-age emergency break fired at session age 50.0h (cap 48h) — cleaning up and exiting.",
+                EmergencyBreakReporter.BuildMessage(50.0, 48, null));
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Program/PostEnrollmentFactsObservedSignalTests.cs

@@ -4,6 +4,7 @@ using AutopilotMonitor.Agent.V2.Core.Logging;
 using AutopilotMonitor.Agent.V2.Core.Orchestration;
 using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
 using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
 using AutopilotMonitor.DecisionCore.Signals;
 using AutopilotMonitor.Shared.Models;
 using Xunit;
@@ -29,7 +30,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Program
             var sink = new FakeSignalIngressSink();
             var logger = NewLogger(tmp.Path);
 
-            AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(sink, logger);
+            AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(sink, HelloWaitTimeout.DefaultSeconds, logger);
 
             Assert.Single(sink.Posted);
             var posted = sink.Posted[0];
@@ -47,7 +48,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Program
             var sink = new FakeSignalIngressSink();
             var logger = NewLogger(tmp.Path);
 
-            AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(sink, logger);
+            AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(sink, HelloWaitTimeout.DefaultSeconds, logger);
 
             var payload = sink.Posted[0].Payload;
             Assert.NotNull(payload);
@@ -73,6 +74,52 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Program
             Assert.True(cloudPc == "true" || cloudPc == "false");
         }
 
+        [Theory]
+        [InlineData(300)] // the default — the payload stays exactly what it was before the key existed
+        [InlineData(30)]  // the old default, still stored for many tenants
+        [InlineData(0)]
+        public void Hello_wait_not_extending_the_built_in_window_is_not_stamped(int helloWaitTimeoutSeconds)
+        {
+            using var tmp = new TempDirectory();
+            var sink = new FakeSignalIngressSink();
+
+            AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(sink, helloWaitTimeoutSeconds, NewLogger(tmp.Path));
+
+            Assert.DoesNotContain(SignalPayloadKeys.HelloWaitTimeoutSeconds, (IDictionary<string, string>)sink.Posted[0].Payload!);
+        }
+
+        [Theory]
+        [InlineData(1800, "1800")]
+        [InlineData(3600, "3600")]
+        [InlineData(86400, "3600")] // the effective (clamped) value is what the engine should arm
+        public void Extended_hello_wait_is_stamped_as_its_effective_value(int helloWaitTimeoutSeconds, string expected)
+        {
+            using var tmp = new TempDirectory();
+            var sink = new FakeSignalIngressSink();
+
+            AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(sink, helloWaitTimeoutSeconds, NewLogger(tmp.Path));
+
+            Assert.Equal(expected, sink.Posted[0].Payload![SignalPayloadKeys.HelloWaitTimeoutSeconds]);
+        }
+
+        [Theory]
+        [InlineData(null, "Shadow")]     // no config value — the default mode
+        [InlineData("Shadow", "Shadow")]
+        [InlineData("active", "Active")] // case-insensitive
+        [InlineData("Off", "Off")]
+        [InlineData("Enforce", "Shadow")] // unknown — changes no decision, still measures
+        public void Oobe_update_phase_mode_is_stamped_at_every_start_normalized(string? configured, string expected)
+        {
+            // D-310: stamped every time, so a later Off/Shadow can take Active away mid-session.
+            using var tmp = new TempDirectory();
+            var sink = new FakeSignalIngressSink();
+
+            AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(
+                sink, HelloWaitTimeout.DefaultSeconds, NewLogger(tmp.Path), configured);
+
+            Assert.Equal(expected, sink.Posted[0].Payload![SignalPayloadKeys.OobeUpdatePhaseMode]);
+        }
+
         [Fact]
         public void Swallows_sink_exceptions()
         {
@@ -82,7 +129,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Program
             var logger = NewLogger(tmp.Path);
 
             var ex = Record.Exception(() =>
-                AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(sink, logger));
+                AutopilotMonitor.Agent.V2.Runtime.LifecycleEmitters.PostEnrollmentFactsObserved(sink, HelloWaitTimeout.DefaultSeconds, logger));
 
             Assert.Null(ex);
         }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Program/ProgramGuardsTests.cs

@@ -149,6 +149,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Program
             persistence.SaveSessionCreatedAt(DateTime.UtcNow.AddHours(-100));
 
             var stateDir = Path.Combine(tmp.Path, "State");
+            double? reportedAgeHours = null;
 
             var tripped = AutopilotMonitor.Agent.V2.Program.CheckSessionAgeEmergencyBreak(
                 dataDirectory: tmp.Path,
@@ -157,9 +158,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Program
                 selfDestructOnComplete: false,
                 cleanupServiceFactory: null,
                 logger: logger,
-                consoleMode: false);
+                consoleMode: false,
+                onBreakFired: ageHours => reportedAgeHours = ageHours);
 
             Assert.True(tripped);
+            // The measured age reaches the break report (the backend cannot derive it).
+            Assert.NotNull(reportedAgeHours);
+            Assert.InRange(reportedAgeHours.Value, 99.9, 100.1);
             // Marker must have been written so the next restart exits cleanly.
             Assert.True(File.Exists(Path.Combine(stateDir, "enrollment-complete.marker")));
             // Session must have been cleared.

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Security/SessionIdPersistenceTests.cs

@@ -3,6 +3,7 @@ using System.IO;
 using AutopilotMonitor.Agent.V2.Core.Logging;
 using AutopilotMonitor.Agent.V2.Core.Security;
 using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
 using Xunit;
 
 namespace AutopilotMonitor.Agent.V2.Core.Tests.Security
@@ -234,5 +235,78 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Security
             Assert.False(File.Exists(Path.Combine(tmp.Path, "session.created")));
             Assert.False(File.Exists(Path.Combine(tmp.Path, "whiteglove.complete")));
         }
+
+        // ============================================================ failed-registration record
+
+        private static RegistrationFailureSummary FailedRun(DateTime at, string outcome = "Failed", bool? linkUpAtEnd = false) =>
+            new RegistrationFailureSummary
+            {
+                FailedRuns = 1,
+                FirstFailedAtUtc = at,
+                LastFailedAtUtc = at,
+                Outcome = outcome,
+                LastError = "No such host is known.",
+                NetworkLinkUpAtStart = false,
+                NetworkLinkUpAtEnd = linkUpAtEnd,
+                AttemptWindowSeconds = 91.3,
+                ConfigFetchOutcome = "UsedDefaults",
+            };
+
+        [Fact]
+        public void RecordRegistrationFailure_counts_runs_keeps_the_first_time_and_describes_the_latest_run()
+        {
+            using var tmp = new TempDirectory();
+            var sut = new SessionIdPersistence(tmp.Path);
+            var first = new DateTime(2026, 8, 20, 9, 0, 0, DateTimeKind.Utc);
+            var second = new DateTime(2026, 9, 12, 7, 30, 0, DateTimeKind.Utc);
+
+            Assert.Null(sut.LoadRegistrationFailure());
+            sut.RecordRegistrationFailure(FailedRun(first));
+            sut.RecordRegistrationFailure(FailedRun(second, outcome: "AuthFailed", linkUpAtEnd: true));
+
+            // A fresh instance reads it back from disk, as the next boot's emergency break does.
+            var record = new SessionIdPersistence(tmp.Path).LoadRegistrationFailure();
+            Assert.NotNull(record);
+            Assert.Equal(2, record!.FailedRuns);
+            Assert.Equal(first, record.FirstFailedAtUtc);
+            Assert.Equal(second, record.LastFailedAtUtc);
+            Assert.Equal("AuthFailed", record.Outcome);
+            Assert.True(record.NetworkLinkUpAtEnd);
+            Assert.Equal(91.3, record.AttemptWindowSeconds);
+            Assert.Equal("UsedDefaults", record.ConfigFetchOutcome);
+        }
+
+        [Fact]
+        public void Registration_failure_record_is_cleared_by_success_delete_and_rotate()
+        {
+            using var tmp = new TempDirectory();
+            var sut = new SessionIdPersistence(tmp.Path);
+            sut.GetOrCreate();
+            var at = new DateTime(2026, 8, 20, 9, 0, 0, DateTimeKind.Utc);
+
+            sut.RecordRegistrationFailure(FailedRun(at));
+            sut.ClearRegistrationFailure();
+            Assert.Null(sut.LoadRegistrationFailure());
+
+            sut.RecordRegistrationFailure(FailedRun(at));
+            sut.Rotate();
+            Assert.Null(sut.LoadRegistrationFailure());
+
+            sut.RecordRegistrationFailure(FailedRun(at));
+            sut.Delete();
+            Assert.Null(sut.LoadRegistrationFailure());
+            Assert.False(File.Exists(Path.Combine(tmp.Path, "registration-failure.json")));
+        }
+
+        [Theory]
+        [InlineData("not json")]
+        [InlineData("{\"FailedRuns\":0}")]
+        public void LoadRegistrationFailure_reports_nothing_for_a_corrupt_or_empty_record(string content)
+        {
+            using var tmp = new TempDirectory();
+            File.WriteAllText(Path.Combine(tmp.Path, "registration-failure.json"), content);
+
+            Assert.Null(new SessionIdPersistence(tmp.Path).LoadRegistrationFailure());
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Security/SessionRegistrationHelperTests.cs

@@ -137,6 +137,86 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Security
             Assert.Equal(originalSessionId, result.RotatedFromSessionId);
         }
 
+        private static BackendRefusalException TenantConflict()
+            => new BackendRefusalException("Backend returned 409 Conflict with error code session_owner_mismatch.", 409,
+                AutopilotMonitor.Shared.Constants.AgentErrorCodes.SessionOwnerMismatch);
+
+        [Fact]
+        public async Task Tenant_conflict_409_rotates_once_like_an_owner_mismatch()
+        {
+            using var tmp = new TempDirectory();
+            var logger = NewLogger(tmp);
+            var config = NewConfig();
+            var originalSessionId = config.SessionId;
+            var rotatedTo = Guid.NewGuid().ToString();
+            var seenSessionIds = new System.Collections.Generic.List<string>();
+
+            var apiClient = new FakeApiClient(
+                attempt => attempt == 1
+                    ? throw TenantConflict()
+                    : new RegisterSessionResponse { Success = true, SessionId = rotatedTo, ValidatedBy = ValidatorType.AutopilotV1 },
+                onRegister: r => seenSessionIds.Add(r.SessionId));
+
+            var tracker = new AuthFailureTracker(maxFailures: 5, timeoutMinutes: 0,
+                clock: SystemClock.Instance, logger: logger);
+
+            var result = await SessionRegistrationHelper.RegisterWithRetryAsync(
+                apiClient, config, agentVersion: "0.0.0", logger: logger,
+                authFailureTracker: tracker,
+                backoffDelay: _ => throw new InvalidOperationException("rotation must retry without backoff"),
+                networkLinkWait: _ => Task.CompletedTask,
+                rotateSession: () => { config.SessionId = rotatedTo; return rotatedTo; });
+
+            Assert.Equal(SessionRegistrationOutcome.Succeeded, result.Outcome);
+            Assert.Equal(new[] { originalSessionId, rotatedTo }, seenSessionIds);
+            Assert.Equal(originalSessionId, result.RotatedFromSessionId);
+            Assert.Equal(0, tracker.ConsecutiveFailures);
+        }
+
+        [Fact]
+        public async Task Coded_refusal_after_rotation_fails_without_retry_or_auth_failure()
+        {
+            using var tmp = new TempDirectory();
+            var logger = NewLogger(tmp);
+            var config = NewConfig();
+
+            var apiClient = new FakeApiClient(_ => throw TenantConflict());
+            var tracker = new AuthFailureTracker(maxFailures: 5, timeoutMinutes: 0,
+                clock: SystemClock.Instance, logger: logger);
+
+            var result = await SessionRegistrationHelper.RegisterWithRetryAsync(
+                apiClient, config, agentVersion: "0.0.0", logger: logger,
+                authFailureTracker: tracker,
+                backoffDelay: _ => throw new InvalidOperationException("a coded refusal must not be retried"),
+                networkLinkWait: _ => Task.CompletedTask,
+                rotateSession: () => { config.SessionId = Guid.NewGuid().ToString(); return config.SessionId; });
+
+            Assert.Equal(SessionRegistrationOutcome.Failed, result.Outcome);
+            Assert.Equal(2, apiClient.CallCount);
+            Assert.Equal(0, tracker.ConsecutiveFailures);
+        }
+
+        [Fact]
+        public async Task Rotation_hook_failure_on_a_tenant_conflict_fails_without_auth_failure()
+        {
+            using var tmp = new TempDirectory();
+            var logger = NewLogger(tmp);
+            var config = NewConfig();
+
+            var apiClient = new FakeApiClient(_ => throw TenantConflict());
+            var tracker = new AuthFailureTracker(maxFailures: 5, timeoutMinutes: 0,
+                clock: SystemClock.Instance, logger: logger);
+
+            var result = await SessionRegistrationHelper.RegisterWithRetryAsync(
+                apiClient, config, agentVersion: "0.0.0", logger: logger,
+                authFailureTracker: tracker, networkLinkWait: _ => Task.CompletedTask,
+                rotateSession: () => throw new IOException("disk full"));
+
+            Assert.Equal(SessionRegistrationOutcome.Failed, result.Outcome);
+            Assert.Equal(1, apiClient.CallCount);
+            Assert.Equal(0, tracker.ConsecutiveFailures);
+        }
+
         [Fact]
         public async Task Second_owner_mismatch_after_rotation_is_an_auth_failure()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/SignalAdapters/EspAndHelloTrackerAdapterTests.cs

@@ -99,6 +99,52 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.SignalAdapters
             Assert.Equal(DecisionSignalKind.WhiteGloveShellCoreSuccess, posted.Kind);
         }
 
+        [Theory]
+        [InlineData(true, "true")]
+        [InlineData(false, "false")]
+        public void WhiteGloveEvent_stamps_read_AccountSetup_progress_on_payload_and_evidence(bool progress, string expected)
+        {
+            using var f = new Fixture();
+            using var adapter = new EspAndHelloTrackerAdapter(
+                f.Coordinator, f.Ingress, f.Clock, accountSetupProgressProbe: () => progress);
+
+            adapter.TriggerWhiteGloveFromTest();
+
+            var posted = Assert.Single(f.Ingress.Posted);
+            Assert.Equal(expected, posted.Payload![SignalPayloadKeys.AccountSetupProgress]);
+            Assert.Equal(expected, posted.Evidence.DerivationInputs![SignalPayloadKeys.AccountSetupProgress]);
+        }
+
+        [Fact]
+        public void WhiteGloveEvent_with_unread_AccountSetup_registry_sends_no_progress_key()
+        {
+            // Unknown must keep the sealing classifier's AccountSetup excluder — the payload key
+            // is absent, the evidence records why.
+            using var f = new Fixture();
+            using var adapter = new EspAndHelloTrackerAdapter(
+                f.Coordinator, f.Ingress, f.Clock, accountSetupProgressProbe: () => null);
+
+            adapter.TriggerWhiteGloveFromTest();
+
+            var posted = Assert.Single(f.Ingress.Posted);
+            Assert.True(posted.Payload == null || !posted.Payload.ContainsKey(SignalPayloadKeys.AccountSetupProgress));
+            Assert.Equal("unread", posted.Evidence.DerivationInputs![SignalPayloadKeys.AccountSetupProgress]);
+        }
+
+        [Fact]
+        public void WhiteGloveEvent_default_probe_on_unstarted_coordinator_reports_unread()
+        {
+            // Production probe: the provisioning tracker does not exist before Start (and never on
+            // Device Preparation) — that is "unread", not "untouched".
+            using var f = new Fixture();
+            using var adapter = new EspAndHelloTrackerAdapter(f.Coordinator, f.Ingress, f.Clock);
+
+            adapter.TriggerWhiteGloveFromTest();
+
+            var posted = Assert.Single(f.Ingress.Posted);
+            Assert.True(posted.Payload == null || !posted.Payload.ContainsKey(SignalPayloadKeys.AccountSetupProgress));
+        }
+
         [Fact]
         public void EspFailureEvent_emits_EspTerminalFailure_with_merged_subSource_annotation()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/SignalAdapters/ImeLogTrackerAdapterPlatformRunTests.cs

@@ -0,0 +1,54 @@
+using System;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.SignalAdapters;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using SharedEventTypes = AutopilotMonitor.Shared.Constants.EventTypes;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.SignalAdapters
+{
+    /// <summary>
+    /// D-316: every emitted platform-script completion carries a run id, and the tracker's run register holds what
+    /// was emitted for it under the IME user id — what the registry reconciliation pairs IME's saved result with.
+    /// </summary>
+    public sealed class ImeLogTrackerAdapterPlatformRunTests
+    {
+        private static readonly DateTime ClockNow = new DateTime(2026, 10, 3, 21, 0, 0, DateTimeKind.Utc);
+        private const string DeviceUser = "00000000-0000-0000-0000-000000000000";
+        private const string PolicyId = "1d6f0a52-3c4e-4b7a-9e21-5f8c7d2b9a10";
+
+        [Fact]
+        public void Platform_completion_carries_its_run_id_and_the_register_holds_the_emitted_run()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddSeconds(-10);
+            f.Tracker.HandlePlatformScriptStarted(PolicyId, "ime", DeviceUser);
+            f.Tracker.RecordPlatformScriptExitCodeForTesting(PolicyId, 0, ClockNow.AddSeconds(-1));
+            f.Tracker.LastMatchedLogTimestamp = ClockNow;
+            f.Tracker.CompletePlatformScriptFromImeResultForTesting(PolicyId, "Success", ClockNow);
+
+            var info = f.InfoEvent(SharedEventTypes.ScriptCompleted);
+            Assert.True(Guid.TryParse(info.Payload!["runId"], out _));
+
+            f.Tracker.ScriptRuns.NotePassCompleted(ClockNow.AddMinutes(1));
+            Assert.Equal(PlatformRunClaim.Claimed, f.Tracker.ScriptRuns.TryClaim(DeviceUser, PolicyId, ClockNow.AddSeconds(5), out var run));
+            Assert.Equal(info.Payload["runId"], run!.RunId);
+            Assert.Equal(0, run.ExitCode);
+            Assert.Equal("Success", run.Result);
+        }
+
+        [Theory]
+        [InlineData("[PowerShell] User Id = 00000000-0000-0000-0000-000000000000, Policy id = d94468af-6ebe-4e94-9901-2a62d33ea6c1, policy result = Success", "00000000-0000-0000-0000-000000000000")]
+        [InlineData(@"Adding argument powershell with value C:\Program Files (x86)\Microsoft Intune Management Extension\Policies\Scripts\6C3F8A20-1D5E-4B97-8F4A-0E2D6B9C7A13_d94468af-6ebe-4e94-9901-2a62d33ea6c1.ps1", "6c3f8a20-1d5e-4b97-8f4a-0e2d6b9c7a13")]
+        [InlineData(@"Script file C:\Program Files (x86)\Microsoft Intune Management Extension\Policies\Scripts\00000000-0000-0000-0000-000000000000_d94468af-6ebe-4e94-9901-2a62d33ea6c1.ps1 is generated", "00000000-0000-0000-0000-000000000000")]
+        [InlineData(@"Adding argument powershellDetection with value C:\Program Files (x86)\Microsoft Intune Management Extension\Content\DetectionScripts\8b2e4c71-6a9d-4f03-b5e8-2c7a1d9f4e36_2.ps1", null)]
+        [InlineData("[PowerShell] User Id = not-a-guid, Policy id = d94468af", null)]
+        [InlineData("", null)]
+        public void Ime_user_id_is_read_from_the_result_line_and_the_script_path(string text, string? expected)
+        {
+            Assert.Equal(expected, ImeLogTracker.ImeUserIdFrom(text));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Termination/EnrollmentTerminationHandlerTests.cs

@@ -564,6 +564,37 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Termination
             Assert.False(File.Exists(Path.Combine(rig.StateDir, "enrollment-complete.marker")));
         }
 
+        [Fact]
+        public void Handle_whiteglove_part1_writes_marker_before_the_later_exit_steps()
+        {
+            // The technician's reseal can kill the process anywhere after the seal. The marker
+            // is what lets the next boot skip the 48-hour break and resume Part 2, so it must
+            // exist before collectors stop, diagnostics upload, grace and drain run.
+            using var rig = new Rig();
+            rig.State = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1")) { Stage = SessionStage.WhiteGloveSealed }.Build();
+            bool? markerPresentAtCollectorStop = null;
+            rig.StopPeripheralCollectorsHook = () => markerPresentAtCollectorStop = rig.SessionPersistence.IsWhiteGloveResume();
+
+            rig.Build().Handle(sender: null!,
+                Args(EnrollmentTerminationReason.DecisionTerminalStage, EnrollmentTerminationOutcome.Succeeded, SessionStage.WhiteGloveSealed));
+
+            Assert.True(markerPresentAtCollectorStop, "whiteglove.complete must be written before the peripheral collectors are stopped.");
+            var emitted = rig.EmittedEventTypes.ToList();
+            Assert.True(emitted.IndexOf("agent_shutting_down") >= 0, "agent_shutting_down must still be emitted.");
+        }
+
+        [Fact]
+        public void Handle_non_whiteglove_termination_never_writes_the_marker()
+        {
+            using var rig = new Rig();
+            rig.State = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1")) { Stage = SessionStage.Completed }.Build();
+
+            rig.Build().Handle(sender: null!,
+                Args(EnrollmentTerminationReason.DecisionTerminalStage, EnrollmentTerminationOutcome.Succeeded, SessionStage.Completed));
+
+            Assert.False(rig.SessionPersistence.IsWhiteGloveResume());
+        }
+
         [Fact]
         public void Handle_whiteglove_part1_stops_collectors_before_emitting_part1_complete()
         {
@@ -902,6 +933,43 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Termination
             Assert.Equal(EnrollmentTerminationOutcome.Failed.ToString(), (string)data["outcome"]);
         }
 
+        [Fact]
+        public void Handle_propagates_stopped_waiting_reason_and_cause_in_agent_shutting_down_data()
+        {
+            // D-310: the engine stopped waiting for the user (no sign-in after the OOBE update).
+            // The backend classifies this shutdown honestly — it keys on the reason tag.
+            using var rig = new Rig();
+            rig.State = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1")) { Stage = SessionStage.EspAccountSetup }.Build();
+
+            rig.Build().Handle(sender: null!, new EnrollmentTerminatedEventArgs(
+                EnrollmentTerminationReason.StoppedWaiting,
+                EnrollmentTerminationOutcome.TimedOut,
+                SessionStage.EspAccountSetup.ToString(),
+                EndUtc,
+                details: StoppedWaitingReasons.Describe(StoppedWaitingReasons.OobeUpdateNoSignIn),
+                stopReason: StoppedWaitingReasons.OobeUpdateNoSignIn));
+
+            var data = rig.DataOf(Constants.EventTypes.AgentShuttingDown);
+            Assert.NotNull(data);
+            Assert.Equal("stopped_waiting", (string)data!["reason"]);
+            Assert.Equal(StoppedWaitingReasons.OobeUpdateNoSignIn, (string)data["stopReason"]);
+            Assert.Equal(EnrollmentTerminationOutcome.TimedOut.ToString(), (string)data["outcome"]);
+        }
+
+        [Fact]
+        public void Handle_omits_stop_reason_for_other_shutdowns()
+        {
+            using var rig = new Rig();
+            rig.State = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1")) { Stage = SessionStage.AwaitingHello }.Build();
+
+            rig.Build().Handle(sender: null!,
+                Args(EnrollmentTerminationReason.MaxLifetimeExceeded, EnrollmentTerminationOutcome.TimedOut, SessionStage.AwaitingHello));
+
+            var data = rig.DataOf(Constants.EventTypes.AgentShuttingDown);
+            Assert.NotNull(data);
+            Assert.False(data!.ContainsKey("stopReason"));
+        }
+
         [Fact]
         public void Handle_includes_uptime_and_agent_version_in_agent_shutting_down()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Transport/BackendApiClientAuthClassificationTests.cs

@@ -88,6 +88,35 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Transport
             Assert.Null(ex.ErrorCode);
         }
 
+        // ── coded 409: a refusal, never an auth failure ─────────────────────
+
+        [Fact]
+        public async Task Coded_409_is_a_refusal_not_an_auth_failure()
+        {
+            using var client = BuildClient(
+                HttpStatusCode.Conflict,
+                "{\"success\":false,\"message\":\"Session id is already registered to another tenant\",\"errorCode\":\"session_owner_mismatch\"}",
+                "application/json");
+
+            var ex = await Assert.ThrowsAsync<BackendRefusalException>(
+                () => client.RegisterSessionAsync(new AutopilotMonitor.Shared.Models.SessionRegistration()));
+
+            Assert.Equal(409, ex.StatusCode);
+            Assert.Equal("session_owner_mismatch", ex.ErrorCode);
+        }
+
+        [Fact]
+        public async Task Uncoded_409_stays_a_plain_http_error()
+        {
+            using var client = BuildClient(
+                HttpStatusCode.Conflict,
+                "{\"success\":false,\"message\":\"A diagnostics package with this name already exists\"}",
+                "application/json");
+
+            await Assert.ThrowsAsync<HttpRequestException>(
+                () => client.GetDiagnosticsUploadUrlAsync("tenant-1", "session-1", "package.zip"));
+        }
+
         [Theory]
         [InlineData(null, null)]
         [InlineData("", null)]

src/Agent/AutopilotMonitor.Agent.V2.Core/Configuration/AgentConfiguration.cs

@@ -157,12 +157,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Configuration
         public double ReplaySpeedFactor { get; set; } = 50;
 
         /// <summary>
-        /// Wait time in seconds after ESP exit before marking Hello as skipped.
-        /// When ESP exits, we wait this duration for Hello wizard to start (event 62404).
-        /// Default: 30 seconds (reasonable for systems under load).
-        /// If Hello wizard starts within this window, we continue waiting for Hello completion (300/301).
+        /// Tenant Hello wait in seconds after the ESP exit, merged from RemoteConfig. Stamped on
+        /// <c>EnrollmentFactsObserved</c> for the decision engine's hello_safety window; the Hello
+        /// tracker gets the same remote value through the collector configuration. Both resolve it
+        /// through <see cref="HelloWaitTimeout.EffectiveSeconds"/> (at least the built-in 300 s,
+        /// at most 3600 s). Default: 300 seconds.
         /// </summary>
-        public int HelloWaitTimeoutSeconds { get; set; } = 30;
+        public int HelloWaitTimeoutSeconds { get; set; } = HelloWaitTimeout.DefaultSeconds;
 
         /// <summary>
         /// Maximum consecutive authentication failures (401/403) before the agent shuts down.

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/CmTraceEraTable.cs

@@ -58,8 +58,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
     ///   (IME service family and AgentExecutor.log: eras are byte ranges).</description></item>
     /// <item><description><see cref="TryResolveByLocalTime"/> — transfer for files written by the
     ///   SAME process as the IME service log but without their own era marker (AppWorkload.log,
-    ///   AppActionProcessor.log: plugins hosted in IntuneManagementExtension.exe, verified in the
-    ///   decompiled build). Within one process every file shares the zone belief, so a local
+    ///   AppActionProcessor.log: plugins hosted in IntuneManagementExtension.exe, verified against
+    ///   the IME build). Within one process every file shares the zone belief, so a local
     ///   timestamp places the line in the service era whose local range contains it. Disabled
     ///   entirely when the service eras' local ranges are not monotonic (a westward zone change
     ///   between two service starts makes the ranges overlap) — ambiguity must never anchor.</description></item>

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeLogTracker.Handlers.cs

@@ -271,17 +271,42 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             }
             else
             {
-                HandlePlatformScriptStarted(id, source);
+                HandlePlatformScriptStarted(id, source, ImeUserIdFrom(match.Value));
             }
         }
 
+        /// <summary>
+        /// The IME user id on a platform-script line — <c>User Id = {id}</c> on the result line,
+        /// <c>…\Policies\Scripts\{id}_{policy}.ps1</c> on the start lines — or null. Read from the
+        /// matched text, not from a capture group, so it works with every pattern pack the agent may
+        /// be served.
+        /// </summary>
+        internal static string ImeUserIdFrom(string text)
+        {
+            if (string.IsNullOrEmpty(text)) return null;
+            const string resultTag = "User Id = ";
+            const string pathTag = @"\Policies\Scripts\";
+            var i = text.IndexOf(resultTag, StringComparison.OrdinalIgnoreCase);
+            if (i >= 0) return GuidAt(text, i + resultTag.Length);
+            i = text.IndexOf(pathTag, StringComparison.OrdinalIgnoreCase);
+            return i >= 0 ? GuidAt(text, i + pathTag.Length) : null;
+        }
+
+        private static string GuidAt(string text, int start)
+        {
+            if (start + 36 > text.Length) return null;
+            var candidate = text.Substring(start, 36);
+            return Guid.TryParse(candidate, out _) ? candidate.ToLowerInvariant() : null;
+        }
+
         // Platform script: AgentExecutor.log entries create/enrich, IME log entries also create.
         // Internal so the stale-slot hardening is directly testable (the public path arrives via
         // a regex Match).
-        internal void HandlePlatformScriptStarted(string id, string source = null)
+        internal void HandlePlatformScriptStarted(string id, string source = null, string userId = null)
         {
             var currentStartTs = LastMatchedLogTimestamp ?? UtcNowProvider();
             var currentStartProvenance = CaptureLastMatchedProvenance();
+            var fromExecutor = string.Equals(source, "agentexecutor", StringComparison.OrdinalIgnoreCase);
 
             // A start line older than the result this policy already emitted is the late start
             // line of THAT run: its AgentExecutor block surfaced after the IME result — the two
@@ -294,7 +319,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             // never tie; a low-resolution clock in a test may).
             if (_platformScriptResultEmitted.TryGetValue(id, out var emittedResultTs) && currentStartTs < emittedResultTs)
             {
-                RecordInvocationMarker(id, isClose: false);
+                RecordInvocationMarker(id, isClose: false, EmittedRunId);
                 NoteInvocationActivity();
                 _logger.Debug($"ImeLogTracker: platform script start line for {id} (source: {source ?? "ime"}) predates its emitted result — late line of that run, not a new one");
                 return;
@@ -302,7 +327,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 
             if (_pendingPlatformScripts.TryGetValue(id, out var pendingSlot))
             {
-                if (pendingSlot.StartedAtUtc.HasValue && currentStartTs - pendingSlot.StartedAtUtc.Value > TimeSpan.FromHours(24))
+                if (pendingSlot.StartedAtUtc.HasValue && currentStartTs - pendingSlot.StartedAtUtc.Value > StalePlatformRunAge)
                 {
                     // Stale-slot hardening (session eaf3d8c4): a replayed start line from a previous
                     // enrollment whose matching result never appeared (script was mid-run when that
@@ -319,6 +344,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     // Emit what the held run has; its end block did not surface in time.
                     EmitPlatformScriptResult(pendingSlot, "the next run of this policy started");
                 }
+                else if (fromExecutor && LastMatchedLogTimestamp.HasValue && pendingSlot.Result == null
+                    && pendingSlot.ExecutorStartedAtUtc.HasValue && pendingSlot.ExecutorStartedAtUtc.Value < currentStartTs)
+                {
+                    // Every executor process writes its start line once: a later one is the next run
+                    // (IME re-runs a failed script on a later check-in), whose end block must not
+                    // overwrite this one's. This run waits for its IME result — on the first pass
+                    // AgentExecutor.log is read in full before the IME log (session eff1b413).
+                    ParkPlatformRun(pendingSlot);
+                }
                 else if (!pendingSlot.StartedAtUtc.HasValue)
                 {
                     // The slot was opened by its result while the start block was still hidden;
@@ -328,7 +362,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     _stateDirty = true;
                 }
             }
-            if (!_pendingPlatformScripts.ContainsKey(id))
+            if (_pendingPlatformScripts.TryGetValue(id, out var slot))
+            {
+                if (slot.UserId == null && userId != null) slot.UserId = userId;
+                if (fromExecutor && !slot.ExecutorStartedAtUtc.HasValue)
+                {
+                    slot.ExecutorStartedAtUtc = currentStartTs;
+                    _stateDirty = true;
+                }
+            }
+            else
             {
                 // A fresh start for this policy (no pending entry) begins a NEW execution.
                 // Clear any emitted-marker from a prior run so IME re-evaluations / retries of
@@ -336,24 +379,29 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 // deduped away. A start line of the emitted run itself never reaches this point
                 // (the guard above), so this never clears the current run's own marker.
                 _platformScriptResultEmitted.Remove(id);
-                _pendingPlatformScripts[id] = new ScriptExecutionState
+                slot = new ScriptExecutionState
                 {
                     PolicyId = id,
                     ScriptType = "platform",
+                    UserId = userId,
+                    RunId = NewRunId(),
                     // Prefer the source CMTrace timestamp so a script that started before the
                     // agent launched (replayed log content) is dated to its real start, not now.
                     // Set only at slot creation: the start line fires twice (agentexecutor + ime
                     // source) but the earliest wins.
                     StartedAtUtc = currentStartTs,
                     StartedAtProvenance = currentStartProvenance,
+                    ExecutorStartedAtUtc = fromExecutor ? currentStartTs : (DateTime?)null,
                 };
+                _pendingPlatformScripts[id] = slot;
+                ScriptRuns.NoteStarted(userId, id, UtcNowProvider());
                 // Live "running" indicator — same signal health scripts emit. Gated on slot
                 // creation so the duplicate start line (agentexecutor + ime source) doesn't
                 // double-emit for the same execution.
                 try { OnScriptStarted?.Invoke(new ScriptStartedInfo { PolicyId = id, ScriptType = "platform" }); }
                 catch (Exception ex) { _logger.Warning($"ImeLogTracker: OnScriptStarted handler threw: {ex.Message}"); }
             }
-            RecordInvocationMarker(id, isClose: false);
+            RecordInvocationMarker(id, isClose: false, LastMatchedLogTimestamp.HasValue ? RunIdOfStartLine(slot, fromExecutor, currentStartTs) : slot.RunId);
             NoteInvocationActivity();
             // Started lines fire twice per script (agentexecutor + ime source) and carry no
             // outcome — the matching `platform script completed` line below carries result+exit
@@ -361,6 +409,34 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             _logger.Debug($"ImeLogTracker: platform script started: {id} (source: {source ?? "ime"})");
         }
 
+        /// <summary>How long after IME's "Script file … is generated" line its executor writes its start line (about 2 s).</summary>
+        private static readonly TimeSpan ImeLaunchWindow = TimeSpan.FromMinutes(1);
+
+        /// <summary>
+        /// The run a timestamped start line belongs to, for its invocation marker. An executor start line belongs to the
+        /// slot unless it is older than the slot's executor start — re-read behind a later run — then to the parked run
+        /// it started. IME's "Script file … is generated" precedes its executor: it belongs to the live run whose
+        /// executor started within <see cref="ImeLaunchWindow"/> after it, else to a slot whose executor has not
+        /// started yet; otherwise its run is not known (yet) and the lines behind it go nowhere.
+        /// </summary>
+        private string RunIdOfStartLine(ScriptExecutionState slot, bool fromExecutor, DateTime lineTs)
+        {
+            if (fromExecutor)
+            {
+                if (!slot.ExecutorStartedAtUtc.HasValue || slot.ExecutorStartedAtUtc.Value <= lineTs) return slot.RunId;
+                var parked = _parkedPlatformScripts.FirstOrDefault(r =>
+                    string.Equals(r.PolicyId, slot.PolicyId, StringComparison.OrdinalIgnoreCase) && r.ExecutorStartedAtUtc == lineTs);
+                return parked?.RunId ?? EmittedRunId;
+            }
+
+            var launched = LivePlatformRuns(slot.PolicyId)
+                .Where(r => r.ExecutorStartedAtUtc.HasValue && r.ExecutorStartedAtUtc.Value >= lineTs && r.ExecutorStartedAtUtc.Value - lineTs <= ImeLaunchWindow)
+                .OrderBy(r => r.ExecutorStartedAtUtc.Value)
+                .FirstOrDefault();
+            if (launched != null) return launched.RunId;
+            return slot.ExecutorStartedAtUtc.HasValue ? EmittedRunId : slot.RunId;
+        }
+
         // Routes line-by-line script-data handlers (context / exitCode / output) to the right
         // accumulator based on the pattern's scriptType parameter. Health-script lines feed the
         // single-slot _pendingHealthScript (the HS-NEW-RESULT JSON delivers the full cycle in one
@@ -439,6 +515,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 ApplyExitCode(script, exitCode, LastMatchedLogTimestamp ?? UtcNowProvider(), CaptureLastMatchedProvenance());
             else if (ownerPolicyId != null)
                 _logger.Debug($"ImeLogTracker: exit code {exitCode} belongs to platform script {ownerPolicyId}, whose completion was already emitted — dropped");
+            else
+                LogLineBehindWriterBoundary($"exit code {exitCode}");
             // An exit code means the executor just wrote its end block and IME is about to
             // write the result — both land at a stale stream position when another process
             // appended meanwhile. Check the ledgers on the next pass.
@@ -465,17 +543,24 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         {
             var outputType = parameters != null && parameters.TryGetValue("outputType", out var ot) ? ot : null;
             var script = GetCurrentScriptForLineUpdate(parameters);
-            if (script == null) return;
+            if (script == null)
+            {
+                LogLineBehindWriterBoundary($"script output ({outputType ?? "combined"})");
+                return;
+            }
 
             // PS-AGENT-OUTPUT captures both stdout and stderr in one pattern
             var output = match.Groups["output"]?.Value;
-            var error = match.Groups["error"]?.Value;
+            var error = match.Groups["error"];
 
-            if (!string.IsNullOrEmpty(output) && !string.IsNullOrEmpty(error))
+            if (error != null && error.Success)
             {
-                // Combined pattern (write output done. output = ..., error = ...)
-                script.Stdout = TruncateOutput(output.Trim());
-                script.Stderr = TruncateOutput(error.Trim());
+                // Combined pattern (write output done. output = ..., error = ...): both texts as
+                // AgentExecutor wrote them to the result files — the error part is the error file
+                // IME judges. The "error from script" line before it is a snapshot taken before the
+                // output readers finished, so this one replaces it, an empty stdout included.
+                script.Stdout = TruncateOutput(output?.Trim());
+                script.Stderr = TruncateOutput(error.Value.Trim());
             }
             else if (string.Equals(outputType, "stderr", StringComparison.OrdinalIgnoreCase))
             {
@@ -507,7 +592,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 
             if (string.IsNullOrEmpty(id)) return;
 
-            CompletePlatformScriptFromImeResult(id, result, LastMatchedLogTimestamp, LastMatchedPatternId, CaptureLastMatchedProvenance());
+            CompletePlatformScriptFromImeResult(id, result, LastMatchedLogTimestamp, LastMatchedPatternId, CaptureLastMatchedProvenance(), ImeUserIdFrom(match.Value));
         }
 
         /// <summary>
@@ -521,48 +606,46 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// line reopened the slot, produced a fallback duplicate (session e7f3c910).
         /// <see cref="FlushPendingPlatformScriptResults"/> emits the held completion.
         /// </summary>
-        internal void CompletePlatformScriptFromImeResult(string policyId, string result, DateTime? resultLineTimestampUtc, string patternId, CmTraceLineProvenance resultProvenance)
+        internal void CompletePlatformScriptFromImeResult(string policyId, string result, DateTime? resultLineTimestampUtc, string patternId, CmTraceLineProvenance resultProvenance, string userId = null)
         {
-            // Dedup: the deadline-based fallback (FlushPendingPlatformScriptResults) may already have
-            // emitted this script from its AgentExecutor exit code because IME's authoritative
-            // PS-SCRIPT-RESULT line arrived late. The fallback carries the same exit code + stdout,
-            // so re-emitting here would duplicate the timeline entry and inflate counts. Drop the
-            // now-redundant pending entry and skip.
-            if (_platformScriptResultEmitted.ContainsKey(policyId))
+            // The result belongs to the run of this policy that started last before its line —
+            // the run in flight, or an earlier one that waits for its result while a later run
+            // already started (ParkPlatformRun).
+            var script = FindRunForResult(policyId, userId, resultLineTimestampUtc);
+            if (script == null)
             {
-                _logger.Debug($"ImeLogTracker: platform script {policyId} PS-SCRIPT-RESULT arrived after fallback emit — skipping duplicate");
-                _pendingPlatformScripts.Remove(policyId);
-                return;
-            }
+                // Dedup: the deadline-based fallback (FlushPendingPlatformScriptResults) may already
+                // have emitted this run from its AgentExecutor end block because IME's authoritative
+                // PS-SCRIPT-RESULT line arrived late, or the same result line is read again.
+                // Re-emitting would duplicate the timeline entry and inflate counts.
+                if (_platformScriptResultEmitted.ContainsKey(policyId))
+                {
+                    _logger.Debug($"ImeLogTracker: platform script {policyId} PS-SCRIPT-RESULT arrived after its run was emitted — skipping duplicate");
+                    return;
+                }
 
-            // Merge with pending AgentExecutor data if available
-            if (_pendingPlatformScripts.TryGetValue(policyId, out var script))
-            {
-                // Stale-result guard: on an intra-lifetime re-run of the same policy, run 1's
-                // late PS-SCRIPT-RESULT can arrive after run 2's start line already created a
-                // fresh slot (the start clears the emitted-marker). Merging would pair run 2's
-                // StartedAtUtc/state with run 1's result and then drop run 2's genuine result at
-                // the marker check above. A result line always postdates its own run's start
-                // line in the source log, so a result older than the pending slot's start
-                // belongs to a previous run — drop it and keep the live slot intact.
-                if (script.StartedAtUtc.HasValue
-                    && resultLineTimestampUtc.HasValue
-                    && resultLineTimestampUtc.Value < script.StartedAtUtc.Value)
+                // Stale-result guard: every run of this policy in flight started after the result
+                // line — a result line always postdates its own run's start line in the source log,
+                // so it belongs to a previous run. Keep the live runs intact.
+                if (HasLivePlatformRun(policyId))
                 {
                     _logger.Debug($"ImeLogTracker: platform script {policyId} result predates the current run's start — stale result from a previous run, skipping");
                     return;
                 }
-            }
-            else
-            {
+
                 script = new ScriptExecutionState
                 {
                     PolicyId = policyId,
-                    ScriptType = "platform"
+                    ScriptType = "platform",
+                    UserId = userId,
+                    RunId = NewRunId(),
                 };
                 _pendingPlatformScripts[policyId] = script;
+                ScriptRuns.NoteStarted(userId, policyId, UtcNowProvider());
             }
 
+            if (script.UserId == null && userId != null) script.UserId = userId;
+            ResolveParkedRunsBefore(script);
             script.Result = result;
             script.ResultSource = "ime_policy_result";
             script.ResultObservedAtUtc = resultLineTimestampUtc ?? UtcNowProvider();
@@ -591,19 +674,150 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         private void EmitPlatformScriptResult(ScriptExecutionState script, string note = null)
         {
             _logger.Info($"ImeLogTracker: platform script completed: {script.PolicyId}, result={script.Result}, exit={script.ExitCode}{(note != null ? $" ({note})" : string.Empty)}");
+            if (string.IsNullOrEmpty(script.RunId)) script.RunId = NewRunId();
             EmitScriptEvent(script);
+            // The register keeps the latest run per (user, policy) for the registry reconciliation:
+            // a run that waited for its result while a later one started must not take that later
+            // run's entry.
+            if (!HasLaterLivePlatformRun(script)) ScriptRuns.NoteEmitted(script, UtcNowProvider());
             // The run's source stamp, capped at the clock: a result line cannot be read before it
             // was written, so a stamp ahead of the clock is a wrong zone assumption on that line
             // (a rewound result resolved in the reader's zone, session 4377911b: +1 h). Left
             // uncapped, the marker made the genuine NEXT run's start line read as a late line of
-            // this run and its result a duplicate.
+            // this run and its result a duplicate. Only ever raised: a run emitted after a later
+            // one must not move the reference back.
             var runStamp = script.ResultObservedAtUtc ?? script.ExitObservedAtUtc ?? UtcNowProvider();
             var nowUtc = UtcNowProvider();
-            _platformScriptResultEmitted[script.PolicyId] = runStamp > nowUtc ? nowUtc : runStamp;
-            _pendingPlatformScripts.Remove(script.PolicyId);
+            var stamp = runStamp > nowUtc ? nowUtc : runStamp;
+            if (!_platformScriptResultEmitted.TryGetValue(script.PolicyId, out var previousStamp) || stamp > previousStamp)
+                _platformScriptResultEmitted[script.PolicyId] = stamp;
+            if (_pendingPlatformScripts.TryGetValue(script.PolicyId, out var current) && ReferenceEquals(current, script))
+                _pendingPlatformScripts.Remove(script.PolicyId);
+            else
+                _parkedPlatformScripts.Remove(script);
             _stateDirty = true;
         }
 
+        private static string NewRunId() => Guid.NewGuid().ToString("D");
+
+        /// <summary>A run older than this by source time is from a previous enrollment, not a run in flight.</summary>
+        private static readonly TimeSpan StalePlatformRunAge = TimeSpan.FromHours(24);
+
+        private static bool SameUserOrUnknown(string a, string b)
+            => a == null || b == null || string.Equals(a, b, StringComparison.OrdinalIgnoreCase);
+
+        private static DateTime StartOf(ScriptExecutionState run) => run.StartedAtUtc ?? DateTime.MinValue;
+
+        /// <summary>The runs of a policy that are not emitted yet: the earlier ones waiting for their IME result, then the one in flight.</summary>
+        private IEnumerable<ScriptExecutionState> LivePlatformRuns(string policyId)
+        {
+            foreach (var run in _parkedPlatformScripts)
+            {
+                if (string.Equals(run.PolicyId, policyId, StringComparison.OrdinalIgnoreCase)) yield return run;
+            }
+            if (_pendingPlatformScripts.TryGetValue(policyId, out var current)) yield return current;
+        }
+
+        private bool HasLivePlatformRun(string policyId) => LivePlatformRuns(policyId).Any();
+
+        /// <summary>The live run a start marker names, or null once that run was emitted.</summary>
+        private ScriptExecutionState FindLivePlatformRun(string policyId, string runId)
+            => LivePlatformRuns(policyId).FirstOrDefault(r => string.Equals(r.RunId, runId, StringComparison.Ordinal));
+
+        private bool HasLaterLivePlatformRun(ScriptExecutionState script)
+            => LivePlatformRuns(script.PolicyId).Any(r => !ReferenceEquals(r, script)
+                && SameUserOrUnknown(r.UserId, script.UserId) && StartOf(r) > StartOf(script));
+
+        /// <summary>
+        /// The live run an IME result line belongs to: of the runs of its policy that started at or before the line,
+        /// the latest — one of the same IME user when there is one.
+        /// </summary>
+        private ScriptExecutionState FindRunForResult(string policyId, string userId, DateTime? resultLineTimestampUtc)
+        {
+            ScriptExecutionState sameUser = null, anyUser = null;
+            foreach (var run in LivePlatformRuns(policyId))
+            {
+                if (resultLineTimestampUtc.HasValue && run.StartedAtUtc.HasValue && run.StartedAtUtc.Value > resultLineTimestampUtc.Value) continue;
+                if (anyUser == null || StartOf(run) > StartOf(anyUser)) anyUser = run;
+                if (SameUserOrUnknown(run.UserId, userId) && (sameUser == null || StartOf(run) > StartOf(sameUser))) sameUser = run;
+            }
+            return sameUser ?? anyUser;
+        }
+
+        /// <summary>
+        /// Moves the run in flight aside when the next executor run of its policy starts: it keeps its own end block and
+        /// waits for its IME result (<see cref="FindRunForResult"/>), the exit-code fallback, or a later run's result.
+        /// </summary>
+        private void ParkPlatformRun(ScriptExecutionState run)
+        {
+            _pendingPlatformScripts.Remove(run.PolicyId);
+            _parkedPlatformScripts.Add(run);
+            _stateDirty = true;
+            if (_parkedPlatformScripts.Count > MaxParkedPlatformScripts)
+            {
+                var oldest = _parkedPlatformScripts.OrderBy(StartOf).First();
+                _logger.Warning($"ImeLogTracker: more than {MaxParkedPlatformScripts} platform runs wait for their IME result — resolving the oldest ({oldest.PolicyId}, started {oldest.StartedAtUtc:o}) now");
+                ResolveParkedRun(oldest, "too many runs waiting for their IME result");
+            }
+            _logger.Debug($"ImeLogTracker: platform script {run.PolicyId}: the next executor run started before IME's result of run {run.RunId} was read — that run keeps its end block and waits for its result");
+        }
+
+        /// <summary>
+        /// Results arrive in run order: a parked run of the same IME user that started before the run a result belongs to
+        /// gets none any more (its result line was lost) — it goes out now, ahead of the later run.
+        /// </summary>
+        private void ResolveParkedRunsBefore(ScriptExecutionState owner)
+        {
+            if (_parkedPlatformScripts.Count == 0 || !owner.StartedAtUtc.HasValue) return;
+            var earlier = _parkedPlatformScripts
+                .Where(r => !ReferenceEquals(r, owner)
+                    && string.Equals(r.PolicyId, owner.PolicyId, StringComparison.OrdinalIgnoreCase)
+                    && SameUserOrUnknown(r.UserId, owner.UserId)
+                    && r.StartedAtUtc.HasValue && r.StartedAtUtc.Value < owner.StartedAtUtc.Value)
+                .OrderBy(StartOf)
+                .ToList();
+            foreach (var run in earlier) ResolveParkedRun(run, "a later run of this policy got its IME result first");
+        }
+
+        /// <summary>A parked run that will not get its IME result: out with what it has, or dropped when it has nothing.</summary>
+        private void ResolveParkedRun(ScriptExecutionState run, string why)
+        {
+            if (run.Result != null)
+            {
+                EmitPlatformScriptResult(run, why);
+            }
+            else if (run.ExitCode.HasValue)
+            {
+                EmitFromExecutorEndBlock(run, why);
+            }
+            else
+            {
+                _parkedPlatformScripts.Remove(run);
+                _stateDirty = true;
+                _logger.Debug($"ImeLogTracker: platform script {run.PolicyId} run {run.RunId} has neither IME result nor executor end block — dropped ({why})");
+            }
+        }
+
+        /// <summary>
+        /// IME's own verdict from a run's end block: Success exactly when the error file was empty
+        /// (<c>IsNullOrEmpty(errorFile.Trim())</c> in IME), whatever the exit code — PowerShell returns 0 after a
+        /// non-terminating error and any code a script exits with. Only when the stderr line was never read does the
+        /// exit code stand in.
+        /// </summary>
+        internal static string ImeResultFromEndBlock(ScriptExecutionState script)
+        {
+            if (script.Stderr != null) return string.IsNullOrWhiteSpace(script.Stderr) ? "Success" : "Failed";
+            return script.ExitCode == 0 ? "Success" : "Failed";
+        }
+
+        private void EmitFromExecutorEndBlock(ScriptExecutionState script, string why)
+        {
+            script.Result = ImeResultFromEndBlock(script);
+            script.ResultSource = "agentexecutor_fallback";
+            var basis = script.Stderr == null ? $"exit code {script.ExitCode}, stderr not read" : script.Stderr.Trim().Length == 0 ? "empty stderr" : "stderr present";
+            EmitPlatformScriptResult(script, $"{why} — {script.Result} from the executor end block ({basis}) (fallback)");
+        }
+
         /// <summary>
         /// Grace period after a platform script's AgentExecutor exit code is observed before
         /// <see cref="FlushPendingPlatformScriptResults"/> emits a completion from that exit code.
@@ -641,29 +855,48 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// out once its executor end block has been read — the block arrives within one pass, so
         /// stdout/stderr are in by now — or after <see cref="PlatformScriptEndBlockGrace"/>.</item>
         /// <item>A script with a known AgentExecutor exit code but no IME <c>PS-SCRIPT-RESULT</c>
-        /// line within <see cref="PlatformScriptResultGrace"/> is emitted from the exit code
-        /// (0 → Success, else Failed), tagged <c>resultSource=agentexecutor_fallback</c> so the
-        /// data is honest about its provenance. Without this, scripts that completed shortly
-        /// before the agent terminates were silently dropped.</item>
+        /// line within <see cref="PlatformScriptResultGrace"/> is emitted from its end block by
+        /// IME's own rule (<see cref="ImeResultFromEndBlock"/>), tagged
+        /// <c>resultSource=agentexecutor_fallback</c> so the data is honest about its provenance.
+        /// Without this, scripts that completed shortly before the agent terminates were silently
+        /// dropped.</item>
         /// </list>
+        /// Parked runs go first, oldest first, so a policy's runs leave in run order; one without
+        /// result and end block keeps waiting — across a shutdown too — until a later run's result
+        /// resolves it or it is a day old.
         /// Runs on the single-threaded polling loop (no locking needed, same as the handlers).
         /// <paramref name="force"/> bypasses both grace checks for the final pass on shutdown.
         /// </summary>
         internal void FlushPendingPlatformScriptResults(DateTime nowUtc, bool force = false)
         {
-            if (_pendingPlatformScripts.Count == 0) return;
+            if (_pendingPlatformScripts.Count == 0 && _parkedPlatformScripts.Count == 0) return;
 
             var fallbackEmitted = false;
-            foreach (var script in _pendingPlatformScripts.Values.ToList())
+            foreach (var run in _parkedPlatformScripts.OrderBy(StartOf).ToList())
             {
-                // Already emitted by the authoritative path — just drop the stale buffer entry.
-                if (_platformScriptResultEmitted.ContainsKey(script.PolicyId))
+                if (run.Result != null)
                 {
-                    _pendingPlatformScripts.Remove(script.PolicyId);
-                    _stateDirty = true;
+                    if (run.ExitCode.HasValue || force || !run.ResultHeldSinceUtc.HasValue || nowUtc - run.ResultHeldSinceUtc.Value >= PlatformScriptEndBlockGrace)
+                        EmitPlatformScriptResult(run, run.ExitCode.HasValue ? "executor end block read after the result" : $"no executor end block within {PlatformScriptEndBlockGrace.TotalSeconds:F0}s");
                     continue;
                 }
+                if (run.ExitCode.HasValue)
+                {
+                    if (!force && (!run.ExitObservedAtUtc.HasValue || nowUtc - run.ExitObservedAtUtc.Value < PlatformScriptResultGrace)) continue;
+                    EmitFromExecutorEndBlock(run, $"result not seen within {PlatformScriptResultGrace.TotalSeconds:F0}s{(force ? ", shutdown flush" : string.Empty)}");
+                    fallbackEmitted = true;
+                    continue;
+                }
+                if (run.StartedAtUtc.HasValue && nowUtc - run.StartedAtUtc.Value > StalePlatformRunAge)
+                {
+                    _parkedPlatformScripts.Remove(run);
+                    _stateDirty = true;
+                    _logger.Debug($"ImeLogTracker: platform script {run.PolicyId} run {run.RunId} waited a day without IME result or executor end block — dropped");
+                }
+            }
 
+            foreach (var script in _pendingPlatformScripts.Values.ToList())
+            {
                 if (script.Result != null)
                 {
                     if (script.ExitCode.HasValue)
@@ -682,10 +915,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     if (nowUtc - script.ExitObservedAtUtc.Value < PlatformScriptResultGrace) continue;
                 }
 
-                script.Result = script.ExitCode.Value == 0 ? "Success" : "Failed";
-                script.ResultSource = "agentexecutor_fallback";
-                EmitPlatformScriptResult(script,
-                    $"result not seen within {PlatformScriptResultGrace.TotalSeconds:F0}s{(force ? ", shutdown flush" : string.Empty)} — emitted from AgentExecutor exit code {script.ExitCode.Value} (fallback)");
+                EmitFromExecutorEndBlock(script, $"result not seen within {PlatformScriptResultGrace.TotalSeconds:F0}s{(force ? ", shutdown flush" : string.Empty)}");
                 fallbackEmitted = true;
             }
 
@@ -697,7 +927,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// <summary>Test seam: inject a pending platform script as if AgentExecutor.log had reported
         /// its start + exit code, without an IME PS-SCRIPT-RESULT line.</summary>
         internal void SeedPendingPlatformScriptForTesting(string policyId, int? exitCode, DateTime? exitObservedAtUtc, string stdout = null, DateTime? startedAtUtc = null,
-            CmTraceLineProvenance startedAtProvenance = null, CmTraceLineProvenance exitProvenance = null)
+            CmTraceLineProvenance startedAtProvenance = null, CmTraceLineProvenance exitProvenance = null, string stderr = null)
         {
             // Mirrors a fresh execution start: a new run clears any prior emitted-marker (see
             // HandleScriptStarted) so re-runs of the same policy within one lifetime emit again.
@@ -706,9 +936,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             {
                 PolicyId = policyId,
                 ScriptType = "platform",
+                RunId = NewRunId(),
                 ExitCode = exitCode,
                 ExitObservedAtUtc = exitObservedAtUtc,
                 Stdout = stdout,
+                Stderr = stderr,
                 StartedAtUtc = startedAtUtc,
                 StartedAtProvenance = startedAtProvenance,
                 ExitProvenance = exitProvenance,
@@ -717,6 +949,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             RecordInvocationMarker(policyId, isClose: false);
         }
 
+        /// <summary>Test seam: earlier runs waiting for their IME result while a later run of their policy is in flight.</summary>
+        internal int ParkedPlatformScriptCountForTest => _parkedPlatformScripts.Count;
+
         /// <summary>Test seam: the authoritative IME PS-SCRIPT-RESULT path for a platform script
         /// (the production handler minus regex extraction). <paramref name="resultLineTimestampUtc"/>
         /// stands in for the CMTrace timestamp of the PS-SCRIPT-RESULT line (production reads it
@@ -1163,11 +1398,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         internal static readonly TimeSpan HeldScriptStartGrace = TimeSpan.FromMinutes(30);
         internal static readonly TimeSpan HeldScriptStartShutdownGrace = TimeSpan.FromMinutes(5);
 
-        private static string TruncateOutput(string output)
+        internal static string TruncateOutput(string output)
         {
             if (string.IsNullOrEmpty(output) || output.Length <= MaxScriptOutputLength)
                 return output;
-            return output.Substring(0, MaxScriptOutputLength) + "...[truncated]";
+            return output.Substring(0, MaxScriptOutputLength) + OutputTruncationMarker;
         }
 
         // -----------------------------------------------------------------------

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeLogTracker.LogProcessing.cs

@@ -123,16 +123,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             var ledger = IsMultiWriterLogFile(fileName) ? GetLedger(fileName) : null;
 
             // Set by a rewind: entries that still read unchanged behind the old bookmark are
-            // skipped, and nothing below the old bookmark is fresh or a calibration anchor.
-            HashSet<LedgerEntry> rewoundEntries = null;
+            // skipped (their invocation markers are given back); a changed entry below the old
+            // bookmark is fresh only when the bytes it replaced were seen moments ago, and never a
+            // calibration anchor.
+            RewindState rewind = null;
             long oldBookmark = -1;
+            var writerBoundaries = IsWriterBoundaryLogFile(fileName);
 
             if (ledger != null)
             {
                 var rewindTo = await PrepareLedgerAsync(filePath, fileName, ledger, startPos, passNowUtc, token);
                 if (rewindTo >= 0)
                 {
-                    rewoundEntries = ApplyRewind(filePath, fileName, ledger, rewindTo, startPos);
+                    rewind = ApplyRewind(filePath, fileName, ledger, rewindTo, startPos);
                     oldBookmark = startPos;
                     startPos = rewindTo;
                 }
@@ -164,21 +167,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             {
                 // Guard zone: the file grew and is open anyway — re-check the entries just behind
                 // the bookmark, where a stale writer's block lands when it is short.
-                if (ledger != null && rewoundEntries == null && ledger.Entries.Count > 0)
+                if (ledger != null && rewind == null && ledger.Entries.Count > 0)
                 {
                     var guardFrom = ledger.OffsetOfEntryAtOrAfter(startPos - OverwriteGuardBytes);
                     if (guardFrom >= 0 && guardFrom < startPos)
                     {
-                        var divergence = await FindOverwriteAsync(stream, ledger, guardFrom, startPos, token);
+                        var divergence = await FindOverwriteAsync(stream, ledger, guardFrom, startPos, passNowUtc, token);
                         _verifiedBytes += startPos - guardFrom;
                         if (divergence >= 0)
                         {
                             // The guard saw only the tail of the ledger; the block may start earlier.
-                            var earliest = await FindOverwriteAsync(stream, ledger, ledger.StartOffset, startPos, token);
+                            var earliest = await FindOverwriteAsync(stream, ledger, ledger.StartOffset, startPos, passNowUtc, token);
                             _verifiedBytes += startPos - ledger.StartOffset;
                             _verifyPasses++;
                             if (earliest >= 0) divergence = earliest;
-                            rewoundEntries = ApplyRewind(filePath, fileName, ledger, divergence, startPos);
+                            rewind = ApplyRewind(filePath, fileName, ledger, divergence, startPos);
                             oldBookmark = startPos;
                             startPos = divergence;
                         }
@@ -259,7 +262,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                         // A fragment right at the bookmark of a multi-writer file (the previous
                         // entry ended exactly here, this one does not open an entry) is the tail of
                         // a block a stale writer laid over already-read bytes: verify before reading on.
-                        if (ledger != null && rewoundEntries == null && entry.Offset == ledger.EndOffset
+                        if (ledger != null && rewind == null && entry.Offset == ledger.EndOffset
                             && ledger.LastFragmentOffset != entry.Offset && !entry.Text.StartsWith("<![LOG["))
                         {
                             ledger.VerifyRequested = true;
@@ -269,11 +272,27 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                         }
                     }
 
-                    if (ledger != null) ledger.Record(entry);
-                    if (rewoundEntries != null && rewoundEntries.Contains(new LedgerEntry { Offset = entry.Offset, Hash = entry.Hash }))
-                        continue; // unchanged behind the old bookmark — processed before the rewind
+                    if (ledger != null) ledger.Record(entry, passNowUtc);
+                    var unchanged = rewind != null && rewind.IsUnchanged(entry);
+                    if (unchanged) RestoreInvocationMarkers(rewind, entry.Offset);
 
-                    _currentPassLinesAreFresh = passLinesAreFresh && entry.Offset >= oldBookmark;
+                    // Writer boundary (see ImeLogTracker.Overwrite.cs): an AgentExecutor.log entry that is
+                    // not exactly one CMTrace record ends the bytes of the executor in front of it. Never
+                    // matched — its text is the cut of two writers. Evaluated for unchanged entries too:
+                    // what owns the position in front of them may have changed with the rewind.
+                    if (writerBoundaries && !IsSingleCmTraceRecord(entry.Text))
+                    {
+                        CloseAtWriterBoundary(fileName, entry.Offset, entry.Text);
+                        continue;
+                    }
+
+                    if (unchanged) continue; // unchanged behind the old bookmark — processed before the rewind
+
+                    // Behind the old bookmark only changed entries arrive here: fresh when the bytes they replaced
+                    // were seen moments ago (RewoundEntryIsFresh), never a calibration anchor.
+                    _currentPassLinesAreFresh = entry.Offset >= oldBookmark
+                        ? passLinesAreFresh
+                        : rewind != null && RewoundEntryIsFresh(passLinesAreFresh, rewind.EntryAtRewindPointReplaced, rewind.OldestReplacedSeenUtc, passNowUtc);
 
                     // --- Normal processing (single-line or completed multiline) ---
                     CmTraceLogEntry parsed;

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeLogTracker.Overwrite.cs

@@ -62,6 +62,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             public long Offset;
             public int Length;
             public ulong Hash;
+            /// <summary>
+            /// When these bytes were last seen as they are (read, seeded or verified unchanged): bytes found different
+            /// at this position later were written after it. Not part of the identity.
+            /// </summary>
+            public DateTime SeenUtc;
 
             // Identity is (offset, hash): a tail first read unterminated and later completed
             // keeps its hash but grows by its terminator.
@@ -100,11 +105,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 return idx < Entries.Count ? Entries[idx].Offset : -1;
             }
 
-            public void Record(AssembledEntry e)
+            public void Record(AssembledEntry e, DateTime seenUtc)
             {
                 var idx = IndexOfFirstAtOrAfter(e.Offset);
                 if (idx < Entries.Count) Entries.RemoveRange(idx, Entries.Count - idx);
-                Entries.Add(new LedgerEntry { Offset = e.Offset, Length = e.Length, Hash = e.Hash });
+                Entries.Add(new LedgerEntry { Offset = e.Offset, Length = e.Length, Hash = e.Hash, SeenUtc = seenUtc });
             }
 
             /// <summary>Drops everything from <paramref name="offset"/> on and returns it — the entries a rewind must not process twice.</summary>
@@ -197,7 +202,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             {
                 ledger.Seeded = true;
                 if (ledger.Entries.Count == 0 && bookmark > 0)
-                    await SeedLedgerAsync(filePath, ledger, bookmark, token).ConfigureAwait(false);
+                    await SeedLedgerAsync(filePath, ledger, bookmark, nowUtc, token).ConfigureAwait(false);
             }
 
             var due = ledger.VerifyRequested || (InContention(nowUtc) && nowUtc >= ledger.NextCadenceVerifyUtc);
@@ -213,7 +218,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 
             long divergence;
             using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
-                divergence = await FindOverwriteAsync(stream, ledger, from, bookmark, token).ConfigureAwait(false);
+                divergence = await FindOverwriteAsync(stream, ledger, from, bookmark, nowUtc, token).ConfigureAwait(false);
             if (token.IsCancellationRequested) return -1;
 
             ledger.VerifyRequested = false;
@@ -228,8 +233,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// Re-reads [fromOffset, toOffset) with the read loop's assembler and compares against the
         /// ledger. Returns the offset of the first entry whose bytes changed — a ledger entry not
         /// reproduced, or an entry the ledger never had — or -1 when everything reads as before.
+        /// Every entry found unchanged is stamped seen at <paramref name="nowUtc"/>.
         /// </summary>
-        private async Task<long> FindOverwriteAsync(FileStream stream, FileLedger ledger, long fromOffset, long toOffset, CancellationToken token)
+        private async Task<long> FindOverwriteAsync(FileStream stream, FileLedger ledger, long fromOffset, long toOffset, DateTime nowUtc, CancellationToken token)
         {
             var entries = ledger.Entries;
             var idx = ledger.IndexOfFirstAtOrAfter(fromOffset);
@@ -255,6 +261,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 if (idx < entries.Count && entries[idx].Offset == e.Offset)
                 {
                     if (entries[idx].Hash != e.Hash) return e.Offset;
+                    var confirmed = entries[idx];
+                    confirmed.SeenUtc = nowUtc;
+                    entries[idx] = confirmed;
                     idx++;
                     continue;
                 }
@@ -265,7 +274,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         }
 
         /// <summary>After a restart the ledger is empty: fingerprint the entries just behind the persisted bookmark without processing them.</summary>
-        private async Task SeedLedgerAsync(string filePath, FileLedger ledger, long bookmark, CancellationToken token)
+        private async Task SeedLedgerAsync(string filePath, FileLedger ledger, long bookmark, DateTime nowUtc, CancellationToken token)
         {
             var from = Math.Max(0, bookmark - RestartSeedBytes);
             using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
@@ -288,18 +297,69 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     if (assembler.Feed(line, reader.LastLineStart, reader.Position, reader.LastLineTruncated, reader.LastLineHash, out e)
                             == CmTraceEntryAssembler.Outcome.Entry
                         && e.Offset + e.Length <= bookmark)
-                        ledger.Record(e);
+                        ledger.Record(e, nowUtc);
                 }
             }
         }
 
-        /// <summary>Moves the bookmark back to the first changed entry; returns the entries to skip if they still read unchanged behind it.</summary>
-        private HashSet<LedgerEntry> ApplyRewind(string filePath, string fileName, FileLedger ledger, long rewindTo, long bookmark)
+        /// <summary>
+        /// What one rewind pass carries: the entries to skip if they still read unchanged behind the rewind point, and
+        /// the invocation markers set aside there until their entries prove unchanged. Pass-local by design — whatever
+        /// is not given back dies with the pass on every exit path.
+        /// </summary>
+        private sealed class RewindState
+        {
+            public RewindState(string fileName, HashSet<LedgerEntry> unchanged, List<InvocationMarker> markers, InvocationMarker lastPlatformMarker, long rewindTo)
+            {
+                FileName = fileName;
+                Unchanged = unchanged;
+                Markers = markers;
+                LastPlatformMarker = lastPlatformMarker;
+                foreach (var replaced in unchanged)
+                {
+                    if (replaced.Offset == rewindTo) EntryAtRewindPointReplaced = true;
+                    if (!OldestReplacedSeenUtc.HasValue || replaced.SeenUtc < OldestReplacedSeenUtc.Value) OldestReplacedSeenUtc = replaced.SeenUtc;
+                }
+            }
+
+            public string FileName { get; }
+            public HashSet<LedgerEntry> Unchanged { get; }
+            /// <summary>Set aside at the rewind, ascending by offset.</summary>
+            public List<InvocationMarker> Markers { get; }
+            /// <summary>The tracker-wide last platform marker, when it was among the set-aside ones.</summary>
+            public InvocationMarker LastPlatformMarker { get; }
+            public int Next { get; set; }
+            /// <summary>The ledger held the entry at the rewind point: the changed bytes lie where something was seen before.</summary>
+            public bool EntryAtRewindPointReplaced { get; }
+            /// <summary>The earliest time any of the replaced bytes was last seen as it was: every changed byte was written after it.</summary>
+            public DateTime? OldestReplacedSeenUtc { get; }
+
+            public bool IsUnchanged(AssembledEntry entry) => Unchanged.Contains(new LedgerEntry { Offset = entry.Offset, Hash = entry.Hash });
+        }
+
+        /// <summary>
+        /// Whether an entry a rewind re-processes (it reads differently than before) is fresh. Its bytes were written after
+        /// the bytes it replaced were last seen as they were — IME stamps a line when it writes it — so when that was at
+        /// most <see cref="FreshLineMaxAge"/> ago the entry's age is bounded like an appended line's and it may anchor
+        /// itself (session d29e27e3: recovered result lines fell back to the agent's stale zone and lost their duration).
+        /// Not fresh when the pass is not (the first pass after a restart never anchors), when the divergence lies in bytes
+        /// the ledger never held (nothing dates them), or when the clock stepped back since.
+        /// </summary>
+        internal static bool RewoundEntryIsFresh(bool passLinesAreFresh, bool entryAtRewindPointReplaced, DateTime? oldestReplacedSeenUtc, DateTime passNowUtc)
+        {
+            if (!passLinesAreFresh || !entryAtRewindPointReplaced || !oldestReplacedSeenUtc.HasValue) return false;
+            var sinceSeen = passNowUtc - oldestReplacedSeenUtc.Value;
+            return sinceSeen >= TimeSpan.Zero && sinceSeen <= FreshLineMaxAge;
+        }
+
+        /// <summary>Moves the bookmark back to the first changed entry; returns what the re-read needs to skip and to give back.</summary>
+        private RewindState ApplyRewind(string filePath, string fileName, FileLedger ledger, long rewindTo, long bookmark)
         {
             var removed = ledger.TruncateFrom(rewindTo);
             _positionTracker.SetPosition(filePath, rewindTo);
             _heldTails.Remove(filePath);
-            InvalidateInvocationMarkersFrom(fileName, rewindTo);
+            var lastPlatformMarker = _lastPlatformMarker;
+            var markers = TakeInvocationMarkersFrom(fileName, rewindTo, out var tookLastPlatformMarker);
             _overwriteRewinds++;
             _overwriteBytesReprocessed += bookmark - rewindTo;
 
@@ -314,7 +374,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             {
                 _logger.Debug(message);
             }
-            return removed;
+            return new RewindState(fileName, removed, markers, tookLastPlatformMarker ? lastPlatformMarker : null, rewindTo);
         }
 
         private long RetentionFloor(string fileName, long bookmark)
@@ -331,20 +391,44 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         // -----------------------------------------------------------------------
         //
         // AgentExecutor.log carries "Powershell exit code is N" / "write output done" without a
-        // policy id. Their owner is decided by FILE POSITION, not by the order lines were read:
-        // an executor writes its end block at its own stream position, i.e. directly after its
-        // own start block in the final bytes, so the nearest preceding invocation marker names
-        // it — and stays right after a rewind re-reads that region. A marker is a platform start
-        // (policy id), some other invocation (detection, remediation, requirement: null) or a
-        // close ("gets invoked" banner, "Agent executor completed").
+        // policy id. Their owner is decided by FILE POSITION: the nearest preceding marker — a
+        // platform start (policy id), some other invocation (detection, remediation, requirement:
+        // null), a close ("gets invoked" banner, "Agent executor completed") or a writer boundary.
+        //
+        // Every executor writes its lines contiguously from its own stream position, so its end
+        // block follows its own start block — but that start block may be gone. Two executors that
+        // open the file at the same end write their start blocks over each other, and the end block
+        // of the one that lost then sits behind the OTHER executor's start block (session 756970cf:
+        // a detection script's exit code and output on a platform script). Where one writer's bytes
+        // meet another's, the cut leaves an entry that is not exactly one CMTrace record — a
+        // fragment, a merged line or an empty line — unless the line boundaries of both writers
+        // coincide byte-exactly. That writer boundary closes the platform invocation in front of it.
+        // AgentExecutor.log only: in the IME log the service writes the markers and the lines they
+        // own itself, and its fragments are executor telemetry lines.
+        //
+        // A marker lives exactly as long as the bytes of its entry: a rewind sets the markers from
+        // the rewind point on aside, and an entry that reads unchanged gets its markers back.
 
         private sealed class InvocationMarker
         {
             public long Offset;
             public string PolicyId;
+            /// <summary>
+            /// The platform run the start line belongs to: the lines behind it go to that run while it is pending or
+            /// waits for its IME result, and nowhere once it was emitted — never to a later run of the same policy.
+            /// Null only on seeded test markers, which resolve by policy.
+            /// </summary>
+            public string RunId;
             public bool IsClose;
+            /// <summary>Set on a writer boundary: the platform invocation it closed.</summary>
+            public string ClosedPolicyId;
         }
 
+        /// <summary>Run id of a start line whose run was emitted already (a late line): owns its lines, matches no live run.</summary>
+        private const string EmittedRunId = "emitted";
+
+        private const string ExecutorLogFileName = "AgentExecutor.log";
+
         private readonly Dictionary<string, List<InvocationMarker>> _invocationMarkers =
             new Dictionary<string, List<InvocationMarker>>(StringComparer.OrdinalIgnoreCase);
         private InvocationMarker _lastPlatformMarker;
@@ -354,24 +438,62 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         private readonly HashSet<string> _platformMarkerFiles = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
         private long _testEntryOrdinal;
 
-        private void RecordInvocationMarker(string policyId, bool isClose)
+        /// <summary>
+        /// The executor log, live or rotated (<c>AgentExecutor-yyyyMMdd-HHmmss.log</c>): its invocations are one process
+        /// each, so a writer boundary ends an invocation — in the final bytes of a rotation as much as in the live file.
+        /// </summary>
+        internal static bool IsWriterBoundaryLogFile(string fileName)
+            => string.Equals(fileName, ExecutorLogFileName, StringComparison.OrdinalIgnoreCase)
+            || (fileName != null
+                && fileName.StartsWith("AgentExecutor-", StringComparison.OrdinalIgnoreCase)
+                && fileName.EndsWith(".log", StringComparison.OrdinalIgnoreCase));
+
+        /// <summary>
+        /// True when the entry is exactly one CMTrace record: it opens with <c>&lt;![LOG[</c> (culture-sensitive like
+        /// <c>CmTraceLogParser.TryParseLine</c>, so a BOM is ignorable) and holds no second one — the parser takes the
+        /// message up to the LAST trailer, so a line cut anywhere, its trailer included, would swallow the record
+        /// written over it. An empty entry is the terminator of a cut line. A script whose own output contains the
+        /// open tag loses that output line: the bytes cannot tell it from a merged line.
+        /// </summary>
+        internal static bool IsSingleCmTraceRecord(string text)
+        {
+            if (string.IsNullOrEmpty(text) || !text.StartsWith(LogOpenTag)) return false;
+            var first = text.IndexOf(LogOpenTag, StringComparison.Ordinal);
+            return first >= 0 && text.IndexOf(LogOpenTag, first + LogOpenTag.Length, StringComparison.Ordinal) < 0;
+        }
+
+        private List<InvocationMarker> GetOrCreateMarkerList(string file)
         {
-            if (_currentEntryOffset < 0) return;
-            var file = _currentSourceFileName ?? TestSourceFileName;
             List<InvocationMarker> list;
             if (!_invocationMarkers.TryGetValue(file, out list))
             {
                 list = new List<InvocationMarker>();
                 _invocationMarkers[file] = list;
             }
+            return list;
+        }
+
+        private static void AppendInvocationMarker(List<InvocationMarker> list, InvocationMarker marker)
+        {
+            if (list.Count >= MaxInvocationMarkersPerFile) list.RemoveAt(0);
+            list.Add(marker);
+        }
+
+        private void RecordInvocationMarker(string policyId, bool isClose, string runId = null)
+        {
+            if (_currentEntryOffset < 0) return;
+            var file = _currentSourceFileName ?? TestSourceFileName;
+            var list = GetOrCreateMarkerList(file);
 
             if (list.Count > 0 && list[list.Count - 1].Offset == _currentEntryOffset)
             {
                 // Two patterns on one line: the platform start outranks the generic argument line.
+                // A writer boundary is never upgraded.
                 var last = list[list.Count - 1];
-                if (!isClose && policyId != null)
+                if (!isClose && policyId != null && last.ClosedPolicyId == null)
                 {
                     last.PolicyId = policyId;
+                    last.RunId = runId;
                     last.IsClose = false;
                     _lastPlatformMarker = last;
                     _platformMarkerFiles.Add(file);
@@ -379,9 +501,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 return;
             }
 
-            if (list.Count >= MaxInvocationMarkersPerFile) list.RemoveAt(0);
-            var marker = new InvocationMarker { Offset = _currentEntryOffset, PolicyId = policyId, IsClose = isClose };
-            list.Add(marker);
+            var marker = new InvocationMarker { Offset = _currentEntryOffset, PolicyId = policyId, RunId = runId, IsClose = isClose };
+            AppendInvocationMarker(list, marker);
             if (!isClose && policyId != null)
             {
                 _lastPlatformMarker = marker;
@@ -390,21 +511,34 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         }
 
         /// <summary>
-        /// The pending platform script that owns the entry being processed, or null.
-        /// <paramref name="ownerPolicyId"/> names the owning platform script even when its slot is
-        /// gone (completion already emitted); null when no platform invocation owns the entry.
+        /// An entry of <paramref name="fileName"/> at <paramref name="offset"/> that is not exactly one CMTrace record:
+        /// the bytes behind it were written by another process than the bytes in front of it. Closes the platform
+        /// invocation that owns the position; records nothing when none is open there (a cut multi-line output yields
+        /// one fragment per line). Idempotent at the same offset.
         /// </summary>
-        private ScriptExecutionState ResolvePlatformScriptForCurrentEntry(out string ownerPolicyId)
+        private void CloseAtWriterBoundary(string fileName, long offset, string text)
+        {
+            var owner = FindOwningMarker(fileName, offset);
+            if (owner == null || owner.IsClose || owner.PolicyId == null) return;
+
+            var list = GetOrCreateMarkerList(fileName);
+            if (list.Count > 0 && list[list.Count - 1].Offset >= offset) return;
+            AppendInvocationMarker(list, new InvocationMarker { Offset = offset, IsClose = true, ClosedPolicyId = owner.PolicyId });
+
+            var kind = string.IsNullOrEmpty(text) ? "empty line" : text.StartsWith(LogOpenTag) ? "merged line" : "fragment";
+            _logger.Debug($"ImeLogTracker: writer boundary in {fileName} at offset {offset} ({kind}, {text?.Length ?? 0} chars) closes platform script {owner.PolicyId} (opened at {owner.Offset}) — the bytes behind it belong to another executor");
+        }
+
+        /// <summary>The marker that owns <paramref name="offset"/> in <paramref name="file"/>, or null.</summary>
+        private InvocationMarker FindOwningMarker(string file, long offset)
         {
-            ownerPolicyId = null;
-            var file = _currentSourceFileName ?? TestSourceFileName;
             InvocationMarker marker = null;
             List<InvocationMarker> list = null;
-            if (_currentEntryOffset >= 0 && _invocationMarkers.TryGetValue(file, out list))
+            if (offset >= 0 && _invocationMarkers.TryGetValue(file, out list))
             {
                 for (var i = list.Count - 1; i >= 0; i--)
                 {
-                    if (list[i].Offset <= _currentEntryOffset)
+                    if (list[i].Offset <= offset)
                     {
                         marker = list[i];
                         break;
@@ -420,24 +554,52 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             // (session 24dc69d1: the health-script worker's exit line pre-filled a platform slot's
             // exit code, its launch line the slot's context).
             if (marker == null && (list == null || list.Count == 0) && _platformMarkerFiles.Contains(file)) marker = _lastPlatformMarker;
+            return marker;
+        }
+
+        /// <summary>
+        /// The pending platform script that owns the entry being processed, or null.
+        /// <paramref name="ownerPolicyId"/> names the owning platform script even when its slot is
+        /// gone (completion already emitted); null when no platform invocation owns the entry.
+        /// </summary>
+        private ScriptExecutionState ResolvePlatformScriptForCurrentEntry(out string ownerPolicyId)
+        {
+            ownerPolicyId = null;
+            var marker = FindOwningMarker(_currentSourceFileName ?? TestSourceFileName, _currentEntryOffset);
             if (marker == null || marker.IsClose || marker.PolicyId == null) return null;
 
             ownerPolicyId = marker.PolicyId;
+            if (marker.RunId != null) return FindLivePlatformRun(marker.PolicyId, marker.RunId);
             ScriptExecutionState state;
             return _pendingPlatformScripts.TryGetValue(marker.PolicyId, out state) ? state : null;
         }
 
-        private void InvalidateInvocationMarkersFrom(string fileName, long offset)
+        /// <summary>Debug trace for an executor line that a writer boundary kept away from a platform script.</summary>
+        private void LogLineBehindWriterBoundary(string what)
         {
+            var marker = FindOwningMarker(_currentSourceFileName ?? TestSourceFileName, _currentEntryOffset);
+            if (marker?.ClosedPolicyId == null) return;
+            _logger.Debug($"ImeLogTracker: {what} at offset {_currentEntryOffset} lies behind the writer boundary at {marker.Offset} that closed platform script {marker.ClosedPolicyId} — another executor's end block, not attributed");
+        }
+
+        /// <summary>Removes the markers from <paramref name="offset"/> on and returns them in offset order.</summary>
+        private List<InvocationMarker> TakeInvocationMarkersFrom(string fileName, long offset, out bool tookLastPlatformMarker)
+        {
+            tookLastPlatformMarker = false;
+            var taken = new List<InvocationMarker>();
             List<InvocationMarker> list;
-            if (!_invocationMarkers.TryGetValue(fileName, out list) || list.Count == 0) return;
-            var removedLast = false;
-            for (var i = list.Count - 1; i >= 0 && list[i].Offset >= offset; i--)
+            if (!_invocationMarkers.TryGetValue(fileName, out list) || list.Count == 0) return taken;
+
+            var from = list.Count;
+            while (from > 0 && list[from - 1].Offset >= offset) from--;
+            for (var i = from; i < list.Count; i++)
             {
-                if (ReferenceEquals(list[i], _lastPlatformMarker)) removedLast = true;
-                list.RemoveAt(i);
+                if (ReferenceEquals(list[i], _lastPlatformMarker)) tookLastPlatformMarker = true;
+                taken.Add(list[i]);
             }
-            if (removedLast)
+            list.RemoveRange(from, list.Count - from);
+
+            if (tookLastPlatformMarker)
             {
                 _lastPlatformMarker = null;
                 for (var i = list.Count - 1; i >= 0; i--)
@@ -449,6 +611,28 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     }
                 }
             }
+            return taken;
+        }
+
+        private void InvalidateInvocationMarkersFrom(string fileName, long offset) => TakeInvocationMarkersFrom(fileName, offset, out _);
+
+        /// <summary>
+        /// An entry that reads unchanged after a rewind keeps its markers: gives back the set-aside markers at exactly
+        /// <paramref name="entryOffset"/>. Set-aside markers in front of it belonged to entries that changed and stay
+        /// gone with their bytes.
+        /// </summary>
+        private void RestoreInvocationMarkers(RewindState rewind, long entryOffset)
+        {
+            var markers = rewind.Markers;
+            while (rewind.Next < markers.Count && markers[rewind.Next].Offset < entryOffset) rewind.Next++;
+            while (rewind.Next < markers.Count && markers[rewind.Next].Offset == entryOffset)
+            {
+                var marker = markers[rewind.Next++];
+                var list = GetOrCreateMarkerList(rewind.FileName);
+                if (list.Count > 0 && list[list.Count - 1].Offset >= marker.Offset) continue;
+                AppendInvocationMarker(list, marker);
+                if (ReferenceEquals(marker, rewind.LastPlatformMarker)) _lastPlatformMarker = marker;
+            }
         }
 
         private long OldestPendingScriptMarkerOffset(string fileName)
@@ -474,6 +658,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// <summary>What a rollover of the file does to its invocation markers.</summary>
         internal void ClearInvocationMarkersForTest(string fileName) => InvalidateInvocationMarkersFrom(fileName, 0);
 
+        internal int InvocationMarkerCountForTest(string fileName)
+            => _invocationMarkers.TryGetValue(fileName, out var list) ? list.Count : 0;
+
         internal int LedgerEntryCountForTest(string fileName)
         {
             FileLedger ledger;

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeLogTracker.cs

@@ -182,6 +182,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         private readonly Dictionary<string, ScriptExecutionState> _pendingPlatformScripts =
             new Dictionary<string, ScriptExecutionState>(StringComparer.OrdinalIgnoreCase);
 
+        // Earlier runs of a policy whose next executor run started before IME's result of them was
+        // read (IME re-runs a failed script on later check-ins; the first pass reads all of
+        // AgentExecutor.log before the IME log). Each keeps its own end block until its result
+        // arrives — session eff1b413 lost that and paired the first result with the last run's block.
+        private readonly List<ScriptExecutionState> _parkedPlatformScripts = new List<ScriptExecutionState>();
+        private const int MaxParkedPlatformScripts = 64;
+
+        /// <summary>
+        /// The platform runs this tracker started and emitted, for the registry reconciliation that
+        /// checks them against IME's saved results (D-316). Shared with the registry host's thread.
+        /// </summary>
+        internal PlatformScriptRunRegister ScriptRuns { get; } = new PlatformScriptRunRegister();
+
         // Health-script (remediation) line-by-line accumulator — single slot because IME
         // executes health scripts SEQUENTIALLY within a session (verified across multiple
         // diagnostic captures: ProcessScript → context → exit → stdout → stderr → compliance,
@@ -240,7 +253,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         // the 32K-char Table Storage property limit that bounds the event downstream. Growth
         // driver is the number of log lines the bootstrap chain writes, so re-measure before
         // adding a chatty step rather than raising this again.
-        private const int MaxScriptOutputLength = 8192;
+        internal const int MaxScriptOutputLength = 8192;
+        internal const string OutputTruncationMarker = "...[truncated]";
         private const int MaxMultiLineBufferLines = 100;
         // Size cap for ONE entry — a single physical line (enforced by BoundedLineReader before
         // the line is materialized) and an assembled multiline entry alike. Any process able to
@@ -389,6 +403,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     VerifiedBytes = _verifiedBytes,
                     PassMaxMs = _passMaxMs,
                     PassGapMaxMs = _passGapMaxMs,
+                    PlatformOutputVerified = ScriptRuns.Verified,
+                    PlatformOutputCorrected = ScriptRuns.Corrected,
                     PatternHits = new Dictionary<string, int>(_patternHits, StringComparer.OrdinalIgnoreCase),
                 };
             }
@@ -1034,6 +1050,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         internal async Task RunPollPassAsync(CancellationToken token)
         {
             var startMs = MonotonicMillisProvider();
+            var passStartedUtc = UtcNowProvider();
             if (_lastPassEndMs >= 0 && startMs - _lastPassEndMs > _passGapMaxMs)
             {
                 _passGapMaxMs = startMs - _lastPassEndMs;
@@ -1045,6 +1062,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             FlushRecurringScripts(UtcNowProvider(), shuttingDown: false);
             CheckPendingTokenFailure(UtcNowProvider());
 
+            // The lines written before this pass started are read now — a held tail or a fragment
+            // awaiting its check follows a pass or two later, which TrackerCatchUp covers. The
+            // registry reconciliation waits for such a pass before it pairs an IME save with a run.
+            if (!token.IsCancellationRequested) ScriptRuns.NotePassCompleted(passStartedUtc);
+            if (ScriptRuns.ConsumeCountersChanged()) _stateDirty = true;
+
             var endMs = MonotonicMillisProvider();
             if (endMs - startMs > _passMaxMs)
             {
@@ -1175,6 +1198,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 }
             }
 
+            _parkedPlatformScripts.Clear();
+            if (state.ParkedPlatformScripts != null)
+            {
+                foreach (var parked in state.ParkedPlatformScripts)
+                {
+                    if (!string.IsNullOrEmpty(parked?.PolicyId) && _parkedPlatformScripts.Count < MaxParkedPlatformScripts)
+                        _parkedPlatformScripts.Add(parked);
+                }
+            }
+
             _scriptTimeoutSuspectedPosted.Clear();
             if (state.ScriptTimeoutSuspectedPosted != null)
             {
@@ -1207,6 +1240,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     _verifiedBytes = state.Health.VerifiedBytes;
                     _passMaxMs = state.Health.PassMaxMs;
                     _passGapMaxMs = state.Health.PassGapMaxMs;
+                    ScriptRuns.RestoreCounters(state.Health.PlatformOutputVerified, state.Health.PlatformOutputCorrected);
                 }
                 if (state.PatternHits != null)
                 {
@@ -1259,6 +1293,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 // must survive restarts — see the LoadState comment for the duplicate scenario.
                 PlatformScriptResultEmittedAt = new Dictionary<string, DateTime>(_platformScriptResultEmitted, StringComparer.OrdinalIgnoreCase),
                 PendingPlatformScripts = _pendingPlatformScripts.Values.ToList(),
+                ParkedPlatformScripts = _parkedPlatformScripts.ToList(),
                 ScriptTimeoutSuspectedPosted = _scriptTimeoutSuspectedPosted.ToList(),
                 RecurringScripts = _recurringScripts.ToPersisted(),
             };
@@ -1283,6 +1318,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     VerifiedBytes = _verifiedBytes,
                     PassMaxMs = _passMaxMs,
                     PassGapMaxMs = _passGapMaxMs,
+                    PlatformOutputVerified = ScriptRuns.Verified,
+                    PlatformOutputCorrected = ScriptRuns.Corrected,
                 };
                 state.PatternHits = new Dictionary<string, int>(_patternHits, StringComparer.OrdinalIgnoreCase);
             }

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeTrackerHealth.cs

@@ -81,6 +81,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// </summary>
         public long PassGapMaxMs { get; set; }
 
+        /// <summary>
+        /// Platform-script runs whose emitted output IME's saved result (registry, after the batch
+        /// report) confirmed — the exit code of the same end block with it. Together with
+        /// <see cref="PlatformOutputCorrected"/> the field measure of the registry reconciliation (D-316).
+        /// </summary>
+        public long PlatformOutputVerified { get; set; }
+
+        /// <summary>Platform-script runs whose emitted output IME's saved result corrected (script_output_reconciliation).</summary>
+        public long PlatformOutputCorrected { get; set; }
+
         /// <summary>Match count per enabled pattern ID — every enabled pattern is present, zeros included.</summary>
         public IReadOnlyDictionary<string, int> PatternHits { get; set; }
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeTrackerStatePersistence.cs

@@ -151,6 +151,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         // that run from the start of the next one.
         public Dictionary<string, DateTime> PlatformScriptResultEmittedAt { get; set; }
         public List<ScriptExecutionState> PendingPlatformScripts { get; set; }
+        // Earlier runs that wait for their IME result while a later run of the same policy is in
+        // flight; a restart between reading AgentExecutor.log and the IME log must keep them. Null on
+        // older state files → none.
+        public List<ScriptExecutionState> ParkedPlatformScripts { get; set; }
         public List<string> ScriptTimeoutSuspectedPosted { get; set; }
 
         // Recurring health-script runs collapsed per policy. Saved in the same write as
@@ -185,6 +189,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         // Poll-loop timing maxima (null-defaulting on older state files).
         public long PassMaxMs { get; set; }
         public long PassGapMaxMs { get; set; }
+        // Registry reconciliation of platform-script output (null-defaulting on older state files).
+        public long PlatformOutputVerified { get; set; }
+        public long PlatformOutputCorrected { get; set; }
     }
 
     public class PackageStateData

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/LogFilePositionTracker.cs

@@ -4,9 +4,9 @@ using System.Collections.Generic;
 namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 {
     /// <summary>
-    /// Tracks file read positions for incremental log file reading.
-    /// In-memory only - resets on agent restart, which is acceptable since
-    /// we start fresh per enrollment session.
+    /// Tracks the IME log tracker's file read positions for incremental log file reading.
+    /// The bookmarks survive agent restarts through the tracker's own state file
+    /// (<see cref="GetAllPositions"/> / <see cref="RestorePosition"/>); the freshness timestamps do not.
     /// </summary>
     public class LogFilePositionTracker
     {

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/PlatformScriptRunRegister.cs

@@ -0,0 +1,196 @@
+using System;
+using System.Collections.Generic;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
+{
+    /// <summary>What the registry reconciliation may do with a saved IME result right now.</summary>
+    internal enum PlatformRunClaim
+    {
+        /// <summary>The run is handed out for reconciliation; it is never handed out again.</summary>
+        Claimed,
+        /// <summary>Not decidable yet: the tracker has not read past the save, or the run is not emitted yet.</summary>
+        Wait,
+        /// <summary>No run of this agent owns the save (none seen, or already reconciled).</summary>
+        None,
+    }
+
+    /// <summary>One platform-script run as the tracker emitted it; the register hands out copies.</summary>
+    internal sealed class PlatformScriptRun
+    {
+        public string PolicyId;
+        public string UserId;
+        public string RunId;
+        public DateTime StartSeenUtc;
+        public bool Emitted;
+        public bool Claimed;
+        public string Result;
+        public string ResultSource;
+        public int? ExitCode;
+        /// <summary>As emitted: null when no output line of the run was read, empty when it said so.</summary>
+        public string Stdout;
+        public string Stderr;
+
+        public PlatformScriptRun Clone() => (PlatformScriptRun)MemberwiseClone();
+    }
+
+    /// <summary>
+    /// The platform-script runs the tracker has seen, the latest per (IME user id, policy id), for the
+    /// registry reconciliation (D-316). IME saves a run's output under
+    /// <c>Policies\&lt;UserId&gt;\&lt;PolicyId&gt;</c> only after it reported the whole script batch, so the
+    /// observer reading it must know which run a changed key belongs to and what was emitted for it.
+    /// Written on the tracker's poll thread, claimed on the registry host's timer thread: every member
+    /// locks, and nothing calls out while holding the lock.
+    /// <para>
+    /// A save belongs to the latest run of its key: IME runs a policy at most once per check-in and
+    /// saves after reporting that check-in's batch, so the next run of the key comes with a later
+    /// check-in. (Overlapping check-ins can run a key twice at once; then IME itself shares the key's
+    /// result files and the judge's foreign verdict is the safety net.) A run that waited for its IME
+    /// result while a later run of its key already started is emitted without touching that later
+    /// run's entry. A save is paired only after the tracker completed a pass that started
+    /// <see cref="TrackerCatchUp"/> after the save was seen — every line written before the save, the
+    /// run's start among them, has been read by then, a stalled poll loop included.
+    /// </para>
+    /// </summary>
+    internal sealed class PlatformScriptRunRegister
+    {
+        /// <summary>
+        /// How far behind a seen save the tracker must have started a completed pass before the save
+        /// is paired; covers the ledger's verify cadence (1 s) for a start line hidden by an overwrite.
+        /// </summary>
+        internal static readonly TimeSpan TrackerCatchUp = TimeSpan.FromSeconds(2);
+
+        internal const int MaxRuns = 256;
+
+        private readonly object _sync = new object();
+        private readonly Dictionary<string, PlatformScriptRun> _latest =
+            new Dictionary<string, PlatformScriptRun>(StringComparer.OrdinalIgnoreCase);
+        private DateTime _lastCompletedPassStartUtc = DateTime.MinValue;
+        private long _verified;
+        private long _corrected;
+        private bool _countersChanged;
+
+        private static string KeyOf(string userId, string policyId) => (userId ?? string.Empty) + "|" + policyId;
+
+        /// <summary>A platform run began: its start line, or its result when no start line was seen.</summary>
+        public void NoteStarted(string userId, string policyId, DateTime seenUtc)
+        {
+            if (string.IsNullOrEmpty(policyId)) return;
+            lock (_sync)
+            {
+                _latest[KeyOf(userId, policyId)] = new PlatformScriptRun { PolicyId = policyId, UserId = userId, StartSeenUtc = seenUtc };
+                TrimLocked();
+            }
+        }
+
+        /// <summary>The tracker emitted the run with these end-block values.</summary>
+        public void NoteEmitted(ScriptExecutionState script, DateTime emittedUtc)
+        {
+            if (script == null || string.IsNullOrEmpty(script.PolicyId)) return;
+            lock (_sync)
+            {
+                var key = KeyOf(script.UserId, script.PolicyId);
+                if (!_latest.TryGetValue(key, out var run) || run.Emitted)
+                {
+                    run = new PlatformScriptRun { PolicyId = script.PolicyId, UserId = script.UserId, StartSeenUtc = emittedUtc };
+                    _latest[key] = run;
+                }
+                run.Emitted = true;
+                run.RunId = script.RunId;
+                run.Result = script.Result;
+                run.ResultSource = script.ResultSource;
+                run.ExitCode = script.ExitCode;
+                run.Stdout = script.Stdout;
+                run.Stderr = script.Stderr;
+                TrimLocked();
+            }
+        }
+
+        /// <summary>The tracker finished a poll pass that started at <paramref name="passStartedUtc"/>.</summary>
+        public void NotePassCompleted(DateTime passStartedUtc)
+        {
+            lock (_sync)
+            {
+                if (passStartedUtc > _lastCompletedPassStartUtc) _lastCompletedPassStartUtc = passStartedUtc;
+            }
+        }
+
+        /// <summary>
+        /// Hands out the run a save of (<paramref name="userId"/>, <paramref name="policyId"/>) seen at
+        /// <paramref name="savedSeenUtc"/> belongs to — once. A run whose user id the tracker could not
+        /// read is keyed without one.
+        /// </summary>
+        public PlatformRunClaim TryClaim(string userId, string policyId, DateTime savedSeenUtc, out PlatformScriptRun run)
+        {
+            run = null;
+            lock (_sync)
+            {
+                if (_lastCompletedPassStartUtc < savedSeenUtc + TrackerCatchUp) return PlatformRunClaim.Wait;
+
+                if (!_latest.TryGetValue(KeyOf(userId, policyId), out var latest)
+                    && !_latest.TryGetValue(KeyOf(null, policyId), out latest))
+                    return PlatformRunClaim.None;
+                if (latest.Claimed) return PlatformRunClaim.None;
+                if (!latest.Emitted) return PlatformRunClaim.Wait;
+
+                latest.Claimed = true;
+                run = latest.Clone();
+                return PlatformRunClaim.Claimed;
+            }
+        }
+
+        public void CountVerified()
+        {
+            lock (_sync) { _verified++; _countersChanged = true; }
+        }
+
+        public void CountCorrected()
+        {
+            lock (_sync) { _corrected++; _countersChanged = true; }
+        }
+
+        /// <summary>Runs whose emitted output IME's saved result confirmed (restart-safe, session-cumulative).</summary>
+        public long Verified { get { lock (_sync) return _verified; } }
+
+        /// <summary>Runs whose emitted output IME's saved result corrected (restart-safe, session-cumulative).</summary>
+        public long Corrected { get { lock (_sync) return _corrected; } }
+
+        public void RestoreCounters(long verified, long corrected)
+        {
+            lock (_sync)
+            {
+                _verified = verified;
+                _corrected = corrected;
+            }
+        }
+
+        /// <summary>True once after a counter moved — the tracker then persists its state.</summary>
+        public bool ConsumeCountersChanged()
+        {
+            lock (_sync)
+            {
+                var changed = _countersChanged;
+                _countersChanged = false;
+                return changed;
+            }
+        }
+
+        private void TrimLocked()
+        {
+            while (_latest.Count > MaxRuns)
+            {
+                string oldestKey = null;
+                var oldest = DateTime.MaxValue;
+                foreach (var kv in _latest)
+                {
+                    if (kv.Value.StartSeenUtc < oldest)
+                    {
+                        oldest = kv.Value.StartSeenUtc;
+                        oldestKey = kv.Key;
+                    }
+                }
+                if (oldestKey == null) return;
+                _latest.Remove(oldestKey);
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ScriptExecutionState.cs

@@ -15,6 +15,28 @@ public class ScriptExecutionState
     /// <summary>"platform" or "remediation".</summary>
     public string ScriptType { get; set; }
 
+    /// <summary>
+    /// IME user id a platform script ran for (the all-zero GUID in device context), read from its
+    /// script path or its result line. Keys IME's saved result
+    /// (<c>Policies\&lt;UserId&gt;\&lt;PolicyId&gt;</c>) that the registry reconciliation compares against.
+    /// </summary>
+    public string UserId { get; set; }
+
+    /// <summary>
+    /// Identity of one platform-script run, given when its slot opens and surfaced as <c>runId</c> on
+    /// the event: the invocation markers bind the run's executor lines to it, and a later
+    /// <c>script_output_reconciliation</c> names it when it corrects that run.
+    /// </summary>
+    public string RunId { get; set; }
+
+    /// <summary>
+    /// Source timestamp of the run's AgentExecutor start line (<c>Adding argument powershell with
+    /// value …</c>). Every executor process writes that line once, so a later one for the same
+    /// policy starts the next run, never this one. Null until the line is read, and on state files
+    /// from before the field.
+    /// </summary>
+    public System.DateTime? ExecutorStartedAtUtc { get; set; }
+
     /// <summary>
     /// UTC timestamp of the script's first observed start line, taken from the source CMTrace log
     /// timestamp (so it dates correctly even when the agent replays historic IME log content that

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/EspAndHelloTracker.cs

@@ -216,6 +216,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// </summary>
         public bool HasAccountSetupProgress => _provisioningTracker?.HasAccountSetupProgress ?? false;
 
+        /// <summary>
+        /// <see cref="ProvisioningStatusTracker.AccountSetupProgressIfRead"/>; <c>null</c> also when
+        /// the provisioning tracker is not running (Device Preparation, before Start). Stamped on
+        /// the WhiteGloveShellCoreSuccess signal for the sealing classifier.
+        /// </summary>
+        public bool? AccountSetupProgressIfRead => _provisioningTracker?.AccountSetupProgressIfRead;
+
         /// <summary>
         /// True once WhiteGlove start has been detected (EventID 509 or persisted from prior run).
         /// Forwarded from ModernDeploymentTracker.
@@ -234,7 +241,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             string tenantId,
             InformationalEventPost post,
             AgentLogger logger,
-            int helloWaitTimeoutSeconds = 30,
+            int helloWaitTimeoutSeconds = HelloWaitTimeout.DefaultSeconds,
             bool modernDeploymentWatcherEnabled = true,
             int modernDeploymentLogLevelMax = 3,
             bool modernDeploymentBackfillEnabled = true,
@@ -359,6 +366,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         public void BackfillRecentHelloWizardStart(int lookbackMinutes)
             => _shellCoreTracker?.BackfillRecentHelloWizardStart(lookbackMinutes);
 
+        /// <summary>
+        /// First run only: the update page's records from before the agent started, as telemetry
+        /// and nothing else — see <see cref="ShellCoreTracker.BackfillUpdatePageTelemetry"/>.
+        /// </summary>
+        public void BackfillUpdatePageTelemetry(int lookbackMinutes)
+            => _shellCoreTracker?.BackfillUpdatePageTelemetry(lookbackMinutes);
+
         /// <summary>
         /// sits-d Cloud-PC fix (2026-08-19) — re-check the user-apps-settled AccountSetup
         /// synthesis after the ESP exit has already been observed. Wired to the IME tracker's
@@ -406,7 +420,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 _tenantId,
                 _post,
                 _logger,
-                _helloTracker);
+                _helloTracker,
+                stateDirectory: _stateDirectory);
             _shellCoreTracker.FinalizingSetupPhaseTriggered += OnFinalizingSetupPhaseTriggered;
             _shellCoreTracker.WhiteGloveCompleted += OnWhiteGloveCompleted;
             _shellCoreTracker.EspFailureDetected += OnShellCoreEspFailureDetected;

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/EventRecordWatermark.cs

@@ -0,0 +1,148 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using Newtonsoft.Json;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
+{
+    /// <summary>
+    /// Cross-restart dedup for event-log watchers that backfill a channel on start. RecordIds are
+    /// per channel, so every watched channel owns one instance with its own state file.
+    /// <para>
+    /// Two boundaries, deliberately separate: the restart watermark is the highest RecordId a
+    /// PRIOR run emitted (loaded once, immutable for this run); the seen-set holds what THIS run
+    /// processed. A single high-water mark would be wrong because the live watcher is armed before
+    /// the backfill runs: a live record with a higher RecordId can arrive first and would then
+    /// make the backfill skip every older, never-emitted record.
+    /// </para>
+    /// </summary>
+    internal sealed class EventRecordWatermark
+    {
+        private readonly string _stateFilePath;
+        private readonly AgentLogger _logger;
+        private readonly string _label;
+        private readonly object _lock = new object();
+        private readonly HashSet<long> _seenThisRun = new HashSet<long>();
+        private long _restartWatermark = -1;
+        private long _maxEmittedRecordId = -1;
+
+        /// <param name="stateDirectory">Directory for the state file; null keeps the dedup in memory only.</param>
+        /// <param name="stateFileName">File name inside <paramref name="stateDirectory"/>.</param>
+        /// <param name="label">Watcher name for log lines.</param>
+        public EventRecordWatermark(string stateDirectory, string stateFileName, AgentLogger logger, string label)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _label = label ?? "EventLog";
+            _stateFilePath = string.IsNullOrEmpty(stateDirectory) || string.IsNullOrEmpty(stateFileName)
+                ? null
+                : Path.Combine(Environment.ExpandEnvironmentVariables(stateDirectory), stateFileName);
+        }
+
+        /// <summary>Highest RecordId emitted by a prior run; -1 when none was persisted.</summary>
+        public long RestartWatermark
+        {
+            get { lock (_lock) return _restartWatermark; }
+        }
+
+        /// <summary>True when the record was already emitted, by a prior run or by this one.</summary>
+        public bool IsAlreadyProcessed(long recordId)
+        {
+            if (recordId < 0) return false; // no RecordId → cannot dedup, let it through
+            lock (_lock)
+            {
+                return recordId <= _restartWatermark || _seenThisRun.Contains(recordId);
+            }
+        }
+
+        /// <summary>
+        /// Atomically claims <paramref name="recordId"/> for this run. True on first sight (the
+        /// caller processes it), false when it was already processed. Records without a RecordId
+        /// (-1) are always claimed, never tracked. Claiming persists nothing — only
+        /// <see cref="MarkEmitted"/> does, so a record that is counted instead of emitted costs no
+        /// state-file write (CBS maintenance writes hundreds of servicing records in seconds).
+        /// </summary>
+        public bool TryClaim(long recordId)
+        {
+            if (recordId < 0) return true;
+            lock (_lock)
+            {
+                return recordId > _restartWatermark && _seenThisRun.Add(recordId);
+            }
+        }
+
+        /// <summary>
+        /// Persists <paramref name="recordId"/> when it raises the emitted maximum, so a restarted
+        /// agent's backfill skips it. Called after the record's event and engine signal were
+        /// handed to the ingress: a crash before that re-emits the record instead of losing it.
+        /// The ingress makes them durable only when its worker appends them to the SignalLog —
+        /// normally milliseconds later; a process killed inside that window (e.g. by a reboot)
+        /// loses the record, and the backfill does not bring it back. Counted records above the
+        /// persisted maximum are counted again after a restart, which only touches the activity
+        /// summary.
+        /// </summary>
+        public void MarkEmitted(long recordId)
+        {
+            if (recordId < 0) return;
+
+            long toPersist = -1;
+            lock (_lock)
+            {
+                if (recordId > _maxEmittedRecordId)
+                {
+                    _maxEmittedRecordId = recordId;
+                    toPersist = recordId;
+                }
+            }
+            if (toPersist >= 0) Persist(toPersist);
+        }
+
+        public void Load()
+        {
+            if (_stateFilePath == null || !File.Exists(_stateFilePath)) return;
+
+            try
+            {
+                var state = JsonConvert.DeserializeObject<WatermarkState>(File.ReadAllText(_stateFilePath));
+                if (state == null) return;
+                lock (_lock)
+                {
+                    _restartWatermark = state.LastRecordId;
+                    _maxEmittedRecordId = state.LastRecordId;
+                }
+                _logger.Info($"{_label} watermark loaded: lastRecordId={state.LastRecordId} (persisted {state.PersistedUtc:O})");
+            }
+            catch (Exception ex)
+            {
+                _logger.Warning($"Failed to load {_label} watermark: {ex.Message}");
+            }
+        }
+
+        private void Persist(long recordId)
+        {
+            if (_stateFilePath == null) return;
+
+            try
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(_stateFilePath));
+                var json = JsonConvert.SerializeObject(
+                    new WatermarkState { LastRecordId = recordId, PersistedUtc = DateTime.UtcNow },
+                    Formatting.Indented);
+                var tempPath = _stateFilePath + ".tmp";
+                File.WriteAllText(tempPath, json);
+                File.Copy(tempPath, _stateFilePath, overwrite: true);
+                try { File.Delete(tempPath); } catch { }
+            }
+            catch (Exception ex)
+            {
+                _logger.Warning($"Failed to persist {_label} watermark: {ex.Message}");
+            }
+        }
+
+        internal sealed class WatermarkState
+        {
+            public long LastRecordId { get; set; }
+            public DateTime PersistedUtc { get; set; }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/HelloTracker.cs

@@ -47,7 +47,6 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
         internal const string HResult_UserSkippedHello = "0x801C044F";
 
-        internal const int HelloCompletionTimeoutSeconds = 300;
         internal const int BackfillLookbackMinutes = 5;
 
         private static readonly HashSet<int> TrackedUdrEventIds = new HashSet<int>
@@ -81,6 +80,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         private readonly InformationalEventPost _post;
         private readonly int _helloWaitTimeoutSeconds;
 
+        // How long a started Hello wizard may take to reach a terminal event (300/301/362): the
+        // tenant's Hello wait resolved through HelloWaitTimeout (300..3600 s). The engine's
+        // hello_safety window spends the same budget from the ESP exit, so this timer never cuts
+        // a user off inside the wizard before the tenant's budget is used up.
+        private readonly int _helloCompletionTimeoutSeconds;
+
         private EventLogWatcher _udrWatcher;
         private EventLogWatcher _helloForBusinessWatcher;
         private System.Threading.Timer _policyCheckTimer;
@@ -121,13 +126,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             string tenantId,
             InformationalEventPost post,
             AgentLogger logger,
-            int helloWaitTimeoutSeconds = 30)
+            int helloWaitTimeoutSeconds = HelloWaitTimeout.DefaultSeconds)
         {
             _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
             _tenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
             _post = post ?? throw new ArgumentNullException(nameof(post));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
             _helloWaitTimeoutSeconds = helloWaitTimeoutSeconds;
+            _helloCompletionTimeoutSeconds = HelloWaitTimeout.EffectiveSeconds(helloWaitTimeoutSeconds);
         }
 
         // =====================================================================
@@ -1094,7 +1100,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 if (policyKnownEnabled)
                 {
                     _logger.Info($"Hello wait timeout ({_helloWaitTimeoutSeconds}s) expired but Hello policy is enabled — " +
-                                 $"wizard not yet visible, starting long completion timer ({HelloCompletionTimeoutSeconds}s)");
+                                 $"wizard not yet visible, starting long completion timer ({_helloCompletionTimeoutSeconds}s)");
 
                     _post.Emit(new EnrollmentEvent
                     {
@@ -1105,7 +1111,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                         Source = "EspAndHelloTracker",
                         Phase = EnrollmentPhase.Unknown,
                         Message = $"Hello wizard did not start within {_helloWaitTimeoutSeconds}s after ESP exit — " +
-                                  $"Hello policy is enabled, waiting up to {HelloCompletionTimeoutSeconds}s for wizard",
+                                  $"Hello policy is enabled, waiting up to {_helloCompletionTimeoutSeconds}s for wizard",
                         Data = new Dictionary<string, object>
                         {
                             { "timeoutSeconds", _helloWaitTimeoutSeconds },
@@ -1205,11 +1211,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             if (_isHelloCompleted) return;
             if (_helloCompletionTimer != null) return;
 
-            _logger.Info($"Starting Hello completion timer ({HelloCompletionTimeoutSeconds}s) - waiting for terminal Hello event (300/301/362)");
+            _logger.Info($"Starting Hello completion timer ({_helloCompletionTimeoutSeconds}s) - waiting for terminal Hello event (300/301/362)");
             _helloCompletionTimer = new System.Threading.Timer(
                 OnHelloCompletionTimeout,
                 null,
-                TimeSpan.FromSeconds(HelloCompletionTimeoutSeconds),
+                TimeSpan.FromSeconds(_helloCompletionTimeoutSeconds),
                 TimeSpan.FromMilliseconds(-1));
         }
 
@@ -1230,7 +1236,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                     return;
                 }
 
-                _logger.Warning($"Hello completion timeout ({HelloCompletionTimeoutSeconds}s) expired after wizard start without terminal event");
+                _logger.Warning($"Hello completion timeout ({_helloCompletionTimeoutSeconds}s) expired after wizard start without terminal event");
                 _isHelloCompleted = true;
                 HelloOutcome = _helloWizardStarted ? "timeout" : "wizard_not_started";
                 StopHelloCompletionTimerLocked();
@@ -1243,10 +1249,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                     Severity = EventSeverity.Warning,
                     Source = "EspAndHelloTracker",
                     Phase = EnrollmentPhase.Unknown,
-                    Message = $"Hello wizard started but no terminal event (300/301/362) arrived within {HelloCompletionTimeoutSeconds}s",
+                    Message = $"Hello wizard started but no terminal event (300/301/362) arrived within {_helloCompletionTimeoutSeconds}s",
                     Data = new Dictionary<string, object>
                     {
-                        { "timeoutSeconds", HelloCompletionTimeoutSeconds },
+                        { "timeoutSeconds", _helloCompletionTimeoutSeconds },
                         { "helloWizardStarted", _helloWizardStarted }
                     },
                     ImmediateUpload = true
@@ -1304,6 +1310,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         internal void TriggerWaitTimeoutForTest() => OnHelloWaitTimeout(null);
         internal void TriggerCompletionTimeoutForTest() => OnHelloCompletionTimeout(null);
 
+        internal int CompletionTimeoutSecondsForTest => _helloCompletionTimeoutSeconds;
         internal bool IsWaitTimerActiveForTest { get { lock (_stateLock) { return _helloWaitTimer != null; } } }
         internal bool IsCompletionTimerActiveForTest { get { lock (_stateLock) { return _helloCompletionTimer != null; } } }
         internal bool IsHelloWizardStartedForTest { get { lock (_stateLock) { return _helloWizardStarted; } } }

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/ImeRegistryAppStateObserver.cs

@@ -360,7 +360,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 : (DateTime?)null;
         }
 
-        /// <summary>StateMessageEnforcementState bands (verified against decompiled IME 1.97/1.104).</summary>
+        /// <summary>StateMessageEnforcementState bands (verified against IME 1.97/1.104).</summary>
         internal static string ClassifyEnforcementState(int state)
         {
             if (state >= 1000 && state < 2000) return "success";

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/ImeRegistryScriptResultObserver.cs

@@ -0,0 +1,401 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text.Json;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.Shared.Models;
+using Microsoft.Win32;
+using SharedEventTypes = AutopilotMonitor.Shared.Constants.EventTypes;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
+{
+    /// <summary>
+    /// Registry second pillar for platform scripts (D-316). After IME reported a script batch to
+    /// Intune it saves every run of the batch under
+    /// <c>HKLM\SOFTWARE\Microsoft\IntuneManagementExtension\Policies\&lt;UserId&gt;\&lt;PolicyId&gt;</c>:
+    /// <c>Result</c>, <c>ErrorCode</c> and <c>ResultDetails</c>, whose <c>ExecutionMsg</c> is what IME read
+    /// from the result file of exactly that policy — the stdout when the run succeeded (IME's Success
+    /// means an empty stderr file, whatever the exit code), the stderr when it failed with ErrorCode 99.
+    /// The log tracker assigns a run's exit code and output by file position in AgentExecutor.log, where
+    /// no policy id anchors them; this observer checks what was emitted against the keyed value and
+    /// emits <c>script_output_reconciliation</c> when they disagree.
+    /// <para>
+    /// Snapshot-and-diff like <see cref="ImeRegistryAppStateObserver"/>, ticked by the same host: the
+    /// first tick is the silent baseline, a later save is paired with its run through
+    /// <see cref="PlatformScriptRunRegister"/>. No exit code lives in the registry: a run whose output
+    /// matches proves the exit code of the same end block; a contradicted run loses its exit code.
+    /// </para>
+    /// </summary>
+    internal sealed class ImeRegistryScriptResultObserver
+    {
+        public const string SourceLabel = "RegistryScriptResult";
+
+        internal const string PoliciesKeyPath = ImeRegistryAppStateObserver.ImeRootKeyPath + @"\Policies";
+
+        /// <summary>A save whose run never became claimable is dropped after this long (send failure of a later batch, agent restart).</summary>
+        internal static readonly TimeSpan PendingExpiry = TimeSpan.FromMinutes(10);
+
+        /// <summary>Safety cap on correction events per agent run; corrections beyond it are counted only.</summary>
+        internal const int MaxCorrectionsPerSession = 100;
+
+        private readonly PlatformScriptRunRegister _runs;
+        private readonly Func<IReadOnlyDictionary<string, SavedScriptResult>> _snapshotSource;
+        private readonly InformationalEventPost _post;
+        private readonly AgentLogger? _logger;
+        private readonly IClock _clock;
+        private readonly object _sync = new object();
+
+        private IReadOnlyDictionary<string, SavedScriptResult>? _last;
+        private readonly Dictionary<string, (SavedScriptResult Saved, DateTime SeenUtc)> _pending =
+            new Dictionary<string, (SavedScriptResult, DateTime)>(StringComparer.OrdinalIgnoreCase);
+        private int _correctionsEmitted;
+
+        /// <param name="snapshotSource">Replaces the live registry walk in tests; per instance, so parallel test classes never share it.</param>
+        public ImeRegistryScriptResultObserver(
+            PlatformScriptRunRegister runs,
+            InformationalEventPost post,
+            AgentLogger? logger,
+            IClock clock,
+            Func<IReadOnlyDictionary<string, SavedScriptResult>>? snapshotSource = null)
+        {
+            _runs = runs ?? throw new ArgumentNullException(nameof(runs));
+            _post = post ?? throw new ArgumentNullException(nameof(post));
+            _clock = clock ?? throw new ArgumentNullException(nameof(clock));
+            _logger = logger;
+            _snapshotSource = snapshotSource ?? ReadSnapshot;
+        }
+
+        /// <summary>One observation pass: snapshot → new saves → pair → judge → correct. Fail-soft: never throws.</summary>
+        public void Tick(string reason)
+        {
+            try
+            {
+                lock (_sync)
+                {
+                    var snapshot = _snapshotSource();
+                    var nowUtc = _clock.UtcNow;
+
+                    if (_last == null)
+                    {
+                        // Saves that predate this agent run belong to runs it never emitted.
+                        _last = snapshot;
+                        _logger?.Info($"RegistryScriptResult: baseline captured ({snapshot.Count} saved platform-script results, trigger={reason})");
+                        return;
+                    }
+
+                    foreach (var kv in snapshot)
+                    {
+                        if (_last.TryGetValue(kv.Key, out var previous) && previous.SameSaveAs(kv.Value)) continue;
+                        _pending[kv.Key] = (kv.Value, nowUtc); // a newer save of the key replaces a waiting one
+                    }
+                    _last = snapshot;
+
+                    ProcessPending(nowUtc);
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger?.Debug($"RegistryScriptResult: tick failed (fail-soft): {ex.Message}");
+            }
+        }
+
+        private void ProcessPending(DateTime nowUtc)
+        {
+            foreach (var key in _pending.Keys.ToList())
+            {
+                var (saved, seenUtc) = _pending[key];
+                var claim = _runs.TryClaim(saved.UserId, saved.PolicyId, seenUtc, out var run);
+                if (claim == PlatformRunClaim.Wait)
+                {
+                    if (nowUtc - seenUtc >= PendingExpiry) _pending.Remove(key);
+                    continue;
+                }
+
+                _pending.Remove(key);
+                if (claim == PlatformRunClaim.Claimed && run != null) Reconcile(run, saved, nowUtc);
+            }
+        }
+
+        private void Reconcile(PlatformScriptRun run, SavedScriptResult saved, DateTime nowUtc)
+        {
+            var judgement = PlatformOutputJudge.Judge(run, saved);
+            switch (judgement.Verdict)
+            {
+                case PlatformOutputVerdict.Verified:
+                    _runs.CountVerified();
+                    _logger?.Debug($"RegistryScriptResult: platform script {run.PolicyId} output confirmed by IME's saved result");
+                    return;
+                case PlatformOutputVerdict.NotComparable:
+                    _logger?.Debug($"RegistryScriptResult: platform script {run.PolicyId} not comparable ({judgement.Reason})");
+                    return;
+            }
+
+            _runs.CountCorrected();
+            if (_correctionsEmitted >= MaxCorrectionsPerSession)
+            {
+                _logger?.Warning($"RegistryScriptResult: correction for {run.PolicyId} not emitted — cap of {MaxCorrectionsPerSession} per agent run reached");
+                return;
+            }
+            _correctionsEmitted++;
+
+            var foreign = judgement.Verdict == PlatformOutputVerdict.Foreign;
+            var culture = CultureInfo.InvariantCulture;
+            var data = new Dictionary<string, string>(StringComparer.Ordinal)
+            {
+                ["policyId"] = run.PolicyId,
+                ["scriptType"] = "platform",
+                ["outcome"] = foreign ? "foreign" : "repaired",
+                ["reason"] = judgement.Reason,
+            };
+            if (!string.IsNullOrEmpty(run.RunId)) data["runId"] = run.RunId!;
+            if (!string.IsNullOrEmpty(saved.Result)) data["result"] = saved.Result!;
+            if (saved.ErrorCode.HasValue) data["registryErrorCode"] = saved.ErrorCode.Value.ToString(culture);
+            // A present key replaces the emitted value, an empty one clears it; an absent key keeps it.
+            if (judgement.Stdout != null) data["stdout"] = judgement.Stdout;
+            if (judgement.Stderr != null) data["stderr"] = judgement.Stderr;
+            if (foreign && run.ExitCode.HasValue) data["previousExitCode"] = run.ExitCode.Value.ToString(culture);
+
+            var shortId = run.PolicyId.Length > 8 ? run.PolicyId.Substring(0, 8) : run.PolicyId;
+            var message = foreign
+                ? $"Platform script {shortId}: output corrected from IME's saved result; the log had attributed another script's output, exit code unverified"
+                : $"Platform script {shortId}: output completed from IME's saved result";
+
+            _post.Emit(
+                eventType: SharedEventTypes.ScriptOutputReconciliation,
+                source: SourceLabel,
+                message: message,
+                severity: foreign ? EventSeverity.Warning : EventSeverity.Info,
+                immediateUpload: foreign,
+                data: data,
+                occurredAtUtc: nowUtc);
+
+            if (foreign)
+                _logger?.Warning($"RegistryScriptResult: platform script {run.PolicyId} run {run.RunId} carried another script's end block ({judgement.Reason}) — corrected from IME's saved result");
+            else
+                _logger?.Info($"RegistryScriptResult: platform script {run.PolicyId} run {run.RunId} output completed from IME's saved result ({judgement.Reason})");
+        }
+
+        // ── snapshot ────────────────────────────────────────────────────────────
+
+        internal static string KeyOf(string userId, string policyId) => userId + "|" + policyId;
+
+        internal static IReadOnlyDictionary<string, SavedScriptResult> ReadSnapshot()
+        {
+            var snapshot = new Dictionary<string, SavedScriptResult>(StringComparer.OrdinalIgnoreCase);
+            using var baseKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64);
+            using var policies = baseKey.OpenSubKey(PoliciesKeyPath);
+            if (policies == null) return snapshot;
+
+            foreach (var userId in policies.GetSubKeyNames())
+            {
+                if (!Guid.TryParse(userId, out _)) continue;
+                using var userKey = policies.OpenSubKey(userId);
+                if (userKey == null) continue;
+
+                foreach (var policyId in userKey.GetSubKeyNames())
+                {
+                    if (!Guid.TryParse(policyId, out _)) continue;
+                    using var policyKey = userKey.OpenSubKey(policyId);
+                    if (policyKey == null) continue;
+
+                    snapshot[KeyOf(userId, policyId)] = new SavedScriptResult
+                    {
+                        UserId = userId,
+                        PolicyId = policyId,
+                        Result = policyKey.GetValue("Result") as string,
+                        ErrorCode = TryReadInt(policyKey.GetValue("ErrorCode")),
+                        ResultDetails = policyKey.GetValue("ResultDetails") as string,
+                        LastUpdatedTimeUtc = policyKey.GetValue("LastUpdatedTimeUtc") as string,
+                    };
+                }
+            }
+            return snapshot;
+        }
+
+        private static int? TryReadInt(object? value)
+        {
+            switch (value)
+            {
+                case int i: return i;
+                case long l when l >= int.MinValue && l <= int.MaxValue: return (int)l;
+                case string s when int.TryParse(s, NumberStyles.Integer, CultureInfo.InvariantCulture, out var parsed): return parsed;
+                default: return null;
+            }
+        }
+    }
+
+    /// <summary>One platform-script result as IME saved it under <c>Policies\&lt;UserId&gt;\&lt;PolicyId&gt;</c>.</summary>
+    internal sealed class SavedScriptResult
+    {
+        public string UserId { get; set; } = string.Empty;
+        public string PolicyId { get; set; } = string.Empty;
+        public string? Result { get; set; }
+        public int? ErrorCode { get; set; }
+        public string? ResultDetails { get; set; }
+        public string? LastUpdatedTimeUtc { get; set; }
+
+        /// <summary>The same save: IME stamps every save with a new <c>LastUpdatedTimeUtc</c>.</summary>
+        public bool SameSaveAs(SavedScriptResult other)
+            => string.Equals(LastUpdatedTimeUtc, other.LastUpdatedTimeUtc, StringComparison.Ordinal)
+            && string.Equals(Result, other.Result, StringComparison.Ordinal)
+            && ErrorCode == other.ErrorCode
+            && string.Equals(ResultDetails, other.ResultDetails, StringComparison.Ordinal);
+
+        /// <summary>
+        /// <c>ExecutionMsg</c> of the CryptoResult JSON in <c>ResultDetails</c> (IME 1.73 and later), or null
+        /// when the value is not that JSON ("Hash mismatch", a launch failure).
+        /// </summary>
+        public string? ExecutionMessage()
+        {
+            if (string.IsNullOrWhiteSpace(ResultDetails)) return null;
+            try
+            {
+                using var doc = JsonDocument.Parse(ResultDetails!);
+                if (doc.RootElement.ValueKind != JsonValueKind.Object) return null;
+                return doc.RootElement.TryGetProperty("ExecutionMsg", out var msg) && msg.ValueKind == JsonValueKind.String
+                    ? msg.GetString()
+                    : null;
+            }
+            catch (JsonException)
+            {
+                return null;
+            }
+        }
+    }
+
+    internal enum PlatformOutputVerdict
+    {
+        /// <summary>IME's saved result cannot confirm or contradict the run (no output saved, other failure kind).</summary>
+        NotComparable,
+        /// <summary>The emitted output is what IME saved: the end block, its exit code included, is the run's own.</summary>
+        Verified,
+        /// <summary>The log delivered the run's output incomplete; IME's saved text completes it, the exit code stands.</summary>
+        Repaired,
+        /// <summary>The emitted output contradicts IME's saved result: the end block was another executor's.</summary>
+        Foreign,
+    }
+
+    internal sealed class PlatformOutputJudgement
+    {
+        public PlatformOutputVerdict Verdict { get; set; }
+        public string Reason { get; set; } = string.Empty;
+        /// <summary>Value to publish (Repaired/Foreign): null keeps the emitted stdout, empty clears it.</summary>
+        public string? Stdout { get; set; }
+        /// <summary>Value to publish (Repaired/Foreign): null keeps the emitted stderr, empty clears it.</summary>
+        public string? Stderr { get; set; }
+    }
+
+    /// <summary>
+    /// Compares a platform-script run as the tracker emitted it with IME's saved result. Comparable are
+    /// a Success (ExecutionMsg = stdout; IME's Success means the stderr file was empty) and a Failed with
+    /// ErrorCode 99 (ExecutionMsg = stderr). Both texts are compared after CR/LF normalisation and Trim;
+    /// the tracker's own 8192-character cut is a prefix of the saved text.
+    /// </summary>
+    internal static class PlatformOutputJudge
+    {
+        internal const int ImeStderrErrorCode = 99;
+        private const string OutputErrorSeparator = ", error =";
+
+        public static PlatformOutputJudgement Judge(PlatformScriptRun run, SavedScriptResult saved)
+        {
+            var executionMessage = saved.ExecutionMessage();
+            if (executionMessage == null) return NotComparable("no_execution_message");
+
+            // The run's IME result line and the save come from the same IME run.
+            if (string.Equals(run.ResultSource, "ime_policy_result", StringComparison.Ordinal)
+                && !string.Equals(run.Result, saved.Result, StringComparison.OrdinalIgnoreCase))
+                return NotComparable("result_differs");
+
+            if (string.Equals(saved.Result, "Success", StringComparison.OrdinalIgnoreCase))
+                return JudgeSuccess(run, Normalize(executionMessage)!);
+            if (string.Equals(saved.Result, "Failed", StringComparison.OrdinalIgnoreCase) && saved.ErrorCode == ImeStderrErrorCode)
+                return JudgeStderrFailure(run, Normalize(executionMessage)!);
+            return NotComparable("no_saved_output");
+        }
+
+        private static PlatformOutputJudgement JudgeSuccess(PlatformScriptRun run, string savedStdout)
+        {
+            var stdout = NormalizeEmitted(run.Stdout, out var stdoutCut);
+            var stderr = Normalize(run.Stderr);
+            var stderrClean = string.IsNullOrEmpty(stderr);
+
+            if (!string.IsNullOrEmpty(stdout) && Agrees(stdout!, stdoutCut, savedStdout))
+                return stderrClean ? Verified() : Correct(PlatformOutputVerdict.Repaired, "stderr_cleared", savedStdout, string.Empty);
+
+            if (stdout != null && stdout.Length == 0 && savedStdout.Length == 0)
+                return stderrClean ? Verified() : Correct(PlatformOutputVerdict.Foreign, "stderr_on_success", string.Empty, string.Empty);
+
+            if (stdout == null)
+            {
+                if (!stderrClean) return Correct(PlatformOutputVerdict.Foreign, "stderr_on_success", savedStdout, string.Empty);
+                return savedStdout.Length > 0
+                    ? Correct(PlatformOutputVerdict.Repaired, "stdout_missing", savedStdout, string.Empty)
+                    : NotComparable("nothing_read");
+            }
+
+            // "write output done. output = X, error = Y" splits at the first ", error =" — a stdout that
+            // contains the separator ends up partly in stderr. The saved text shows the cut right there.
+            if (stdout.Length > 0 && !stdoutCut && !stderrClean
+                && savedStdout.StartsWith(stdout, StringComparison.Ordinal)
+                && savedStdout.Substring(stdout.Length).TrimStart().StartsWith(OutputErrorSeparator, StringComparison.Ordinal))
+                return Correct(PlatformOutputVerdict.Repaired, "stdout_split", savedStdout, string.Empty);
+
+            return Correct(PlatformOutputVerdict.Foreign, "stdout_differs", savedStdout, string.Empty);
+        }
+
+        private static PlatformOutputJudgement JudgeStderrFailure(PlatformScriptRun run, string savedStderr)
+        {
+            var stderr = NormalizeEmitted(run.Stderr, out var stderrCut);
+            if (!string.IsNullOrEmpty(stderr) && Agrees(stderr!, stderrCut, savedStderr)) return Verified();
+
+            // Nothing of the end block read: complete the stderr, the run's stdout stays as emitted.
+            if (run.Stderr == null && run.Stdout == null)
+                return Correct(PlatformOutputVerdict.Repaired, "stderr_missing", null, savedStderr);
+
+            // The end block read said something else — an empty stderr included: IME read stderr from this
+            // run's error file. The block's stdout is the other executor's as well.
+            return Correct(PlatformOutputVerdict.Foreign, "stderr_differs", string.Empty, savedStderr);
+        }
+
+        private static bool Agrees(string emitted, bool emittedCut, string saved)
+            => string.Equals(emitted, saved, StringComparison.Ordinal)
+            || (emittedCut && saved.StartsWith(emitted, StringComparison.Ordinal));
+
+        /// <summary>CR LF and lone CR to LF, then Trim — what the tracker's line reader and handlers make of a text.</summary>
+        internal static string? Normalize(string? text)
+            => text?.Replace("\r\n", "\n").Replace('\r', '\n').Trim();
+
+        private static string? NormalizeEmitted(string? text, out bool cut)
+        {
+            cut = false;
+            if (text == null) return null;
+            if (text.EndsWith(ImeLogTracker.OutputTruncationMarker, StringComparison.Ordinal))
+            {
+                cut = true;
+                text = text.Substring(0, text.Length - ImeLogTracker.OutputTruncationMarker.Length);
+            }
+            return Normalize(text);
+        }
+
+        private static PlatformOutputJudgement Verified()
+            => new PlatformOutputJudgement { Verdict = PlatformOutputVerdict.Verified, Reason = "match" };
+
+        private static PlatformOutputJudgement NotComparable(string reason)
+            => new PlatformOutputJudgement { Verdict = PlatformOutputVerdict.NotComparable, Reason = reason };
+
+        private static PlatformOutputJudgement Correct(PlatformOutputVerdict verdict, string reason, string? stdout, string? stderr)
+            => new PlatformOutputJudgement
+            {
+                Verdict = verdict,
+                Reason = reason,
+                // The tracker's own output cap: a corrected value is never longer than an emitted one.
+                Stdout = stdout == null ? null : ImeLogTracker.TruncateOutput(stdout),
+                Stderr = stderr == null ? null : ImeLogTracker.TruncateOutput(stderr),
+            };
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/OobeUpdateRegistrySnapshot.cs

@@ -0,0 +1,157 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using Microsoft.Win32;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
+{
+    /// <summary>
+    /// Reads the registry state behind the OOBE quality update (D-310, S4/S5): the NDUP state
+    /// Windows keeps while the update page runs, and both policy paths of the ESP setting "Install
+    /// Windows quality updates". <see cref="OobeUpdateTelemetry"/> logs it and reports it as
+    /// <c>oobe_update_state</c>. Read-only; the values are update-state flags and policy values,
+    /// no user data.
+    /// </summary>
+    internal static class OobeUpdateRegistrySnapshot
+    {
+        /// <summary>The snapshot's keys, each with the alias it carries in <c>oobe_update_state</c>.</summary>
+        internal static readonly (string Alias, string Path)[] Keys =
+        {
+            ("setupOobeNdup", @"SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OOBE\NDUP"),
+            ("setupOobeNdupUpdates", @"SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OOBE\NDUP\Updates"),
+            ("ndup", @"SOFTWARE\Microsoft\Windows\CurrentVersion\NDUP"),
+            ("ndupUpdates", @"SOFTWARE\Microsoft\Windows\CurrentVersion\NDUP\Updates"),
+            ("espSetupPolicy", @"SOFTWARE\Microsoft\Windows\Autopilot\EnrollmentStatusTracking\Device\Setup\Policy"),
+            ("policyManagerSystem", PolicyManagerSystemKey),
+            ("policiesOobe", @"SOFTWARE\Policies\Microsoft\Windows\OOBE"),
+        };
+
+        // Carries every System policy of the device; only the OOBE ones belong in this snapshot.
+        internal const string PolicyManagerSystemKey = @"SOFTWARE\Microsoft\PolicyManager\current\device\System";
+
+        internal const int MaxEntries = 30;
+        internal const int MaxValueLength = 200;
+
+        /// <summary>One key of the snapshot: whether it exists, whether it holds values, and its line.</summary>
+        internal sealed class KeyState
+        {
+            public KeyState(string alias, string path, bool exists, bool hasValues, string line)
+            {
+                Alias = alias;
+                Path = path;
+                Exists = exists;
+                HasValues = hasValues;
+                Line = line;
+            }
+
+            public string Alias { get; }
+            public string Path { get; }
+            public bool Exists { get; }
+
+            /// <summary>
+            /// True when the key holds at least one value — for <see cref="PolicyManagerSystemKey"/>
+            /// one with OOBE in its name. Subkeys alone are no values.
+            /// </summary>
+            public bool HasValues { get; }
+
+            /// <summary><see cref="FormatEntries"/> plus the subkey names; null when the key is absent.</summary>
+            public string Line { get; }
+        }
+
+        /// <summary>Reads every key from the 64-bit view. Throws on a registry failure; the caller is fail-soft.</summary>
+        public static IReadOnlyList<KeyState> Read()
+        {
+            var states = new List<KeyState>(Keys.Length);
+            using (var hklm = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64))
+            {
+                foreach (var (alias, path) in Keys)
+                {
+                    using (var key = hklm.OpenSubKey(path))
+                    {
+                        if (key == null)
+                        {
+                            states.Add(new KeyState(alias, path, exists: false, hasValues: false, line: null));
+                            continue;
+                        }
+
+                        var entries = key.GetValueNames()
+                            .Select(name => new KeyValuePair<string, object>(name, key.GetValue(name)))
+                            .ToList();
+                        states.Add(Describe(alias, path, entries, key.GetSubKeyNames()));
+                    }
+                }
+            }
+            return states;
+        }
+
+        /// <summary>The state of a present key from its values and subkey names.</summary>
+        internal static KeyState Describe(string alias, string path, IReadOnlyList<KeyValuePair<string, object>> entries, string[] subKeys)
+        {
+            var oobeOnly = string.Equals(path, PolicyManagerSystemKey, StringComparison.OrdinalIgnoreCase);
+            var line = FormatEntries(entries, oobeOnly);
+            if (subKeys != null && subKeys.Length > 0)
+                line += $" | subkeys: {string.Join(", ", subKeys.Take(MaxEntries))}";
+            return new KeyState(alias, path, exists: true,
+                hasValues: entries.Any(e => !oobeOnly || IsOobeName(e.Key)), line: line);
+        }
+
+        /// <summary>One agent.log line per present key, one naming the absent keys.</summary>
+        public static void Log(AgentLogger logger, string moment, IReadOnlyList<KeyState> states)
+        {
+            if (logger == null || states == null) return;
+
+            var absent = new List<string>();
+            foreach (var state in states)
+            {
+                if (!state.Exists)
+                {
+                    absent.Add(state.Path);
+                    continue;
+                }
+                logger.Info($"OOBE update registry ({moment}): HKLM\\{state.Path}: {state.Line}");
+            }
+
+            if (absent.Count > 0)
+                logger.Info($"OOBE update registry ({moment}): absent: {string.Join(", ", absent)}");
+        }
+
+        /// <summary>
+        /// <c>name=value</c> pairs ordered by name, bounded in count and length.
+        /// <paramref name="oobeOnly"/> keeps only names that mention OOBE.
+        /// </summary>
+        internal static string FormatEntries(IEnumerable<KeyValuePair<string, object>> entries, bool oobeOnly)
+        {
+            var selected = entries
+                .Where(e => !oobeOnly || IsOobeName(e.Key))
+                .OrderBy(e => e.Key, StringComparer.OrdinalIgnoreCase)
+                .ToList();
+            if (selected.Count == 0) return oobeOnly ? "(no OOBE values)" : "(no values)";
+
+            var shown = selected.Take(MaxEntries)
+                .Select(e => $"{(e.Key.Length == 0 ? "(default)" : e.Key)}={FormatValue(e.Value)}");
+            var line = string.Join(", ", shown);
+            return selected.Count > MaxEntries ? $"{line}, … (+{selected.Count - MaxEntries} more)" : line;
+        }
+
+        internal static string FormatValue(object value)
+        {
+            string text;
+            switch (value)
+            {
+                case null: text = "(null)"; break;
+                case int i: text = i.ToString(CultureInfo.InvariantCulture); break;
+                case long l: text = l.ToString(CultureInfo.InvariantCulture); break;
+                case string s: text = s; break;
+                case string[] multi: text = string.Join("|", multi); break;
+                case byte[] bytes: text = $"(binary {bytes.Length} bytes)"; break;
+                default: text = Convert.ToString(value, CultureInfo.InvariantCulture) ?? string.Empty; break;
+            }
+            return text.Length > MaxValueLength ? text.Substring(0, MaxValueLength) + "…" : text;
+        }
+
+        private static bool IsOobeName(string name) =>
+            name != null && name.IndexOf("OOBE", StringComparison.OrdinalIgnoreCase) >= 0;
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/OobeUpdateTelemetry.cs

@@ -0,0 +1,307 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Shared;
+using AutopilotMonitor.Shared.Models;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
+{
+    /// <summary>
+    /// One CloudExperienceHost record of the OOBE update page, parsed by
+    /// <see cref="ShellCoreTracker.ParseUpdatePageRecord"/>.
+    /// </summary>
+    internal sealed class OobeUpdatePageRecord
+    {
+        public const string PageStarted = "page_started";
+        public const string PageStopped = "page_stopped";
+        public const string EventName = "event_name";
+
+        /// <summary>
+        /// Not a record: the <c>cxhEvent</c> of the marker <see cref="OobeUpdateTelemetry"/> sends
+        /// once per budget when the event names of a run start staying in agent.log.
+        /// </summary>
+        public const string NamesCapped = "names_capped";
+
+        public OobeUpdatePageRecord(string cxhEvent, int windowsEventId, string page = null, string result = null, string name = null, string value = null)
+        {
+            CxhEvent = cxhEvent;
+            WindowsEventId = windowsEventId;
+            Page = page;
+            Result = result;
+            Name = name;
+            Value = value;
+        }
+
+        /// <summary><see cref="PageStarted"/>, <see cref="PageStopped"/> or <see cref="EventName"/>.</summary>
+        public string CxhEvent { get; }
+        public int WindowsEventId { get; }
+
+        /// <summary>The page's CXID (start), or the page a stop is attributed to.</summary>
+        public string Page { get; }
+
+        /// <summary>The page result of a stop.</summary>
+        public string Result { get; }
+
+        /// <summary>The event name of a 62406/62407 record.</summary>
+        public string Name { get; }
+
+        /// <summary>A 62407 value of a safe form (boolean, integer, HRESULT); null otherwise.</summary>
+        public string Value { get; }
+    }
+
+    /// <summary>
+    /// Measurement telemetry of the OOBE quality update (D-310): the update page's
+    /// CloudExperienceHost records as <c>oobe_update_page</c> and the registry state behind it as
+    /// <c>oobe_update_state</c>. Debug, bounded per agent run, no decisions. Owned by
+    /// <see cref="ShellCoreTracker"/>, which observes the page.
+    /// </summary>
+    internal sealed class OobeUpdateTelemetry
+    {
+        internal const int MaxPageEventsPerRun = 150;
+
+        /// <summary>
+        /// Event names the backfills (first run, restart) report per run — their own budget, so
+        /// the records from before the agent started cannot spend the live page's.
+        /// </summary>
+        internal const int MaxBackfillPageEventsPerRun = 150;
+
+        internal const int MaxPageEventsPerKey = 3;
+        internal const int MaxStateEventsPerRun = 6;
+        internal const int MaxStateLineLength = 1000;
+
+        /// <summary>When a registry snapshot is taken (<c>moment</c> of <c>oobe_update_state</c>).</summary>
+        internal static class Moments
+        {
+            public const string AgentStart = "agent_start";
+            public const string UpdatePageStarted = "update_page_started";
+            public const string UpdatePageStopped = "update_page_stopped";
+            public const string AgentStop = "agent_stop";
+        }
+
+        private const string Source = Constants.EventSources.ShellCoreTracker;
+
+        private readonly string _sessionId;
+        private readonly string _tenantId;
+        private readonly InformationalEventPost _post;
+        private readonly AgentLogger _logger;
+        private readonly Func<IReadOnlyList<OobeUpdateRegistrySnapshot.KeyState>> _readRegistry;
+
+        private readonly object _lock = new object();
+        private readonly Dictionary<string, int> _pageEventsPerKey = new Dictionary<string, int>(StringComparer.Ordinal);
+        private int _livePageEvents;
+        private int _backfillPageEvents;
+        private bool _liveCapReported;
+        private bool _backfillCapReported;
+        private int _stateEvents;
+        private string _lastStateContent;
+
+        public OobeUpdateTelemetry(
+            string sessionId,
+            string tenantId,
+            InformationalEventPost post,
+            AgentLogger logger,
+            Func<IReadOnlyList<OobeUpdateRegistrySnapshot.KeyState>> readRegistry)
+        {
+            _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
+            _tenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
+            _post = post ?? throw new ArgumentNullException(nameof(post));
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _readRegistry = readRegistry ?? throw new ArgumentNullException(nameof(readRegistry));
+        }
+
+        /// <summary>
+        /// One <c>oobe_update_page</c> per update-page record, at most
+        /// <see cref="MaxPageEventsPerKey"/> per page/name — a page that logs the same name in a
+        /// loop cannot flood the session. Event names also share a budget per run: live ones
+        /// <see cref="MaxPageEventsPerRun"/>, backfilled ones <see cref="MaxBackfillPageEventsPerRun"/>;
+        /// the first name over a budget sends the <see cref="OobeUpdatePageRecord.NamesCapped"/>
+        /// marker. A page start or stop is outside the budgets, because the time attribution reads
+        /// the update's span from them. True when the record was reported.
+        /// </summary>
+        public bool ReportPage(OobeUpdatePageRecord record, DateTime occurredAtUtc, bool isBackfill)
+        {
+            if (record == null) return false;
+
+            var isEventName = record.CxhEvent == OobeUpdatePageRecord.EventName;
+            var key = $"{record.CxhEvent}:{record.Page ?? record.Name}";
+            var budget = isBackfill ? MaxBackfillPageEventsPerRun : MaxPageEventsPerRun;
+            var occurrence = 0;
+            bool overBudget;
+            var firstOverBudget = false;
+            lock (_lock)
+            {
+                overBudget = isEventName && (isBackfill ? _backfillPageEvents : _livePageEvents) >= budget;
+                if (overBudget)
+                {
+                    firstOverBudget = isBackfill ? !_backfillCapReported : !_liveCapReported;
+                    if (isBackfill) _backfillCapReported = true;
+                    else _liveCapReported = true;
+                }
+                else
+                {
+                    _pageEventsPerKey.TryGetValue(key, out occurrence);
+                    if (occurrence >= MaxPageEventsPerKey) return false;
+                    occurrence++;
+                    _pageEventsPerKey[key] = occurrence;
+                    if (isEventName)
+                    {
+                        if (isBackfill) _backfillPageEvents++;
+                        else _livePageEvents++;
+                    }
+                }
+            }
+
+            if (overBudget)
+            {
+                if (firstOverBudget) ReportNamesCapped(budget, occurredAtUtc, isBackfill);
+                return false;
+            }
+
+            var data = new Dictionary<string, object>
+            {
+                { "cxhEvent", record.CxhEvent },
+                { "windowsEventId", record.WindowsEventId },
+                { "eventTime", occurredAtUtc.ToString("o") },
+                { "backfill", isBackfill },
+                { "occurrence", occurrence },
+            };
+            if (record.Page != null) data["page"] = record.Page;
+            if (record.Result != null) data["result"] = record.Result;
+            if (record.Name != null) data["name"] = record.Name;
+            if (record.Value != null) data["value"] = record.Value;
+
+            return EmitPage(occurredAtUtc, DescribePage(record), data);
+        }
+
+        /// <summary>
+        /// The marker that a budget is spent: from here on this run's live or backfilled event
+        /// names stay in agent.log, so a name missing from the session proves nothing — the
+        /// analyze rules that read an absent name check for this marker first.
+        /// </summary>
+        private void ReportNamesCapped(int budget, DateTime occurredAtUtc, bool isBackfill)
+        {
+            var kind = isBackfill ? "backfilled " : string.Empty;
+            _logger.Info($"OOBE update page telemetry: {budget} {kind}event names reached, the rest of this run stays in agent.log");
+
+            EmitPage(occurredAtUtc,
+                $"OOBE update page: {budget} {kind}event names reached, later ones of this agent run are not sent",
+                new Dictionary<string, object>
+                {
+                    { "cxhEvent", OobeUpdatePageRecord.NamesCapped },
+                    { "eventTime", occurredAtUtc.ToString("o") },
+                    { "backfill", isBackfill },
+                    { "limit", budget },
+                });
+        }
+
+        private bool EmitPage(DateTime occurredAtUtc, string message, Dictionary<string, object> data)
+        {
+            try
+            {
+                _post.Emit(new EnrollmentEvent
+                {
+                    SessionId = _sessionId,
+                    TenantId = _tenantId,
+                    Timestamp = occurredAtUtc,
+                    EventType = Constants.EventTypes.OobeUpdatePage,
+                    Severity = EventSeverity.Debug,
+                    Source = Source,
+                    Phase = EnrollmentPhase.Unknown,
+                    Message = message,
+                    Data = data,
+                    ImmediateUpload = false,
+                });
+                return true;
+            }
+            catch (Exception ex)
+            {
+                _logger.Debug($"OOBE update page telemetry failed: {ex.Message}");
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Reads the OOBE update registry state, logs it and reports it as <c>oobe_update_state</c>
+        /// — only when at least one key holds values and the content changed since the last report
+        /// of this run, at most <see cref="MaxStateEventsPerRun"/> times. Fail-soft.
+        /// </summary>
+        public void ReportState(string moment, string page = null)
+        {
+            var label = page == null ? moment : $"{moment} {page}";
+            IReadOnlyList<OobeUpdateRegistrySnapshot.KeyState> states;
+            try
+            {
+                states = _readRegistry() ?? Array.Empty<OobeUpdateRegistrySnapshot.KeyState>();
+            }
+            catch (Exception ex)
+            {
+                _logger.Debug($"OOBE update registry ({label}): snapshot failed: {ex.Message}");
+                return;
+            }
+
+            OobeUpdateRegistrySnapshot.Log(_logger, label, states);
+
+            var withValues = states.Where(s => s.HasValues).ToList();
+            if (withValues.Count == 0) return;
+
+            var content = string.Join("\n", withValues.Select(s => $"{s.Alias}={s.Line}"));
+            lock (_lock)
+            {
+                if (string.Equals(content, _lastStateContent, StringComparison.Ordinal)) return;
+                if (_stateEvents >= MaxStateEventsPerRun) return;
+                _lastStateContent = content;
+                _stateEvents++;
+            }
+
+            var data = new Dictionary<string, object>
+            {
+                { "moment", moment },
+                { "keysWithValues", withValues.Count },
+            };
+            if (page != null) data["page"] = page;
+            foreach (var state in withValues)
+            {
+                data[state.Alias] = state.Line.Length > MaxStateLineLength
+                    ? state.Line.Substring(0, MaxStateLineLength) + "…"
+                    : state.Line;
+            }
+
+            try
+            {
+                _post.Emit(new EnrollmentEvent
+                {
+                    SessionId = _sessionId,
+                    TenantId = _tenantId,
+                    EventType = Constants.EventTypes.OobeUpdateState,
+                    Severity = EventSeverity.Debug,
+                    Source = Source,
+                    Phase = EnrollmentPhase.Unknown,
+                    Message = $"OOBE update registry state ({label}): {withValues.Count} key(s) with values",
+                    Data = data,
+                    ImmediateUpload = false,
+                });
+            }
+            catch (Exception ex)
+            {
+                _logger.Debug($"OOBE update state telemetry failed: {ex.Message}");
+            }
+        }
+
+        private static string DescribePage(OobeUpdatePageRecord record)
+        {
+            switch (record.CxhEvent)
+            {
+                case OobeUpdatePageRecord.PageStarted:
+                    return $"OOBE update page started: {record.Page}";
+                case OobeUpdatePageRecord.PageStopped:
+                    return $"OOBE update page stopped: {record.Page} (result: {record.Result})";
+                default:
+                    return record.Value == null
+                        ? $"OOBE update page event: {record.Name}"
+                        : $"OOBE update page event: {record.Name} = {record.Value}";
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/ProvisioningStatusTracker.cs

@@ -254,16 +254,27 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// host to tell the real user-ESP page exit from the Device→Account handoff exit; not a
         /// completion input.
         /// </summary>
-        public bool HasAccountSetupProgress
+        public bool HasAccountSetupProgress => AccountSetupProgressIfRead == true;
+
+        /// <summary>
+        /// Tri-state form of <see cref="HasAccountSetupProgress"/>: <c>null</c> until the tracker
+        /// has actually read AccountSetup subcategories (not started yet, category not written,
+        /// empty), otherwise whether one has left <c>notStarted</c>. The WhiteGlove sealing
+        /// classifier treats only a read <c>false</c> as "user ESP untouched" — an unread
+        /// registry must never pass for an untouched one.
+        /// </summary>
+        public bool? AccountSetupProgressIfRead
         {
             get
             {
                 lock (_stateLock)
                 {
                     if (_lastSubcategoryStates == null)
-                        return false;
-                    if (!_lastSubcategoryStates.TryGetValue("AccountSetupCategory.Status", out var subs) || subs == null)
-                        return false;
+                        return null;
+                    if (!_lastSubcategoryStates.TryGetValue("AccountSetupCategory.Status", out var subs)
+                        || subs == null
+                        || subs.Count == 0)
+                        return null;
                     foreach (var state in subs.Values)
                     {
                         if (!string.Equals(state, "notStarted", StringComparison.OrdinalIgnoreCase))
@@ -279,7 +290,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// with subcategoryState=succeeded. NOT a WhiteGlove indicator: on Win11 25H2 (build
         /// 26200+) Windows writes this property as a trivially-succeeding step in EVERY
         /// enrollment (validated 2026-08-18 — user-driven sessions f475e697/c601a24b/4219203f
-        /// all carry it). Kept for observability only (whiteglove_signal_* raw dumps); must not
+        /// all carry it). Kept for observability only (save_result_step_* raw dumps); must not
         /// be used for classification. Reliable WhiteGlove anchors are ModernDeployment
         /// EventID 509 and the Shell-Core WhiteGlove-success events.
         /// </summary>
@@ -966,8 +977,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                                     _logger.Info($"ProvisioningStatusTracker: SaveWhiteGloveSuccessResult state " +
                                                  $"transition: {previousState} -> {state}");
 
+                                    // Neutral trigger name: the step exists in every 25H2 enrollment,
+                                    // and "whiteglove_*" was read as a pre-provisioning signal.
                                     EmitRawRegistryDump(categoryLabel, jsonValue,
-                                        $"whiteglove_signal_{state}");
+                                        $"save_result_step_{state}");
 
                                     if (string.Equals(state, "succeeded", StringComparison.OrdinalIgnoreCase))
                                     {

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/ServicingTracker.cs

@@ -0,0 +1,373 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Eventing.Reader;
+using System.Linq;
+using System.Xml.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.DecisionCore.State;
+using AutopilotMonitor.Shared;
+using AutopilotMonitor.Shared.Models;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
+{
+    /// <summary>
+    /// Watches the CBS servicing steps of OS updates in the <c>Setup</c> log
+    /// (<c>Microsoft-Windows-Servicing</c>, D-310): 1 initiating changes (current → target state),
+    /// 2 target state reached, 3 failed, 4 a restart is needed to finish, 6 failed and partially
+    /// installed. The Windows Update client logs only the start of an installation; these steps
+    /// show the long part of it — staging, installing, "reboot required" right before the restart.
+    /// <para>
+    /// Only packages of the OS update clients (<c>UpdateAgentLCU</c> for the cumulative update,
+    /// <c>WindowsUpdateAgent</c>) are emitted as <c>windows_update_servicing</c> and reported to
+    /// the decision engine; language packs, features on demand and DISM operations started by
+    /// apps are counted into the host's <see cref="UpdateActivityTally"/>.
+    /// </para>
+    /// </summary>
+    internal sealed class ServicingTracker : IDisposable
+    {
+        internal const string Channel = "Setup";
+        internal const string ProviderName = "Microsoft-Windows-Servicing";
+
+        internal const int EventId_InitiatingChanges = 1;
+        internal const int EventId_StateReached = 2;
+        internal const int EventId_ChangeFailed = 3;
+        internal const int EventId_RebootRequired = 4;
+        internal const int EventId_PartiallyInstalled = 6;
+
+        internal static readonly int[] TargetedEventIds =
+        {
+            EventId_InitiatingChanges, EventId_StateReached, EventId_ChangeFailed, EventId_RebootRequired, EventId_PartiallyInstalled,
+        };
+
+        internal const string WatermarkStateFileName = "servicing-watermark.json";
+
+        // CBS client ids of the Windows Update installers (seen on 24H2/25H2: UpdateAgentLCU).
+        private static readonly HashSet<string> OsUpdateClients = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+        {
+            "UpdateAgentLCU",
+            "WindowsUpdateAgent",
+        };
+
+        private readonly AgentLogger _logger;
+        private readonly string _sessionId;
+        private readonly string _tenantId;
+        private readonly InformationalEventPost _post;
+        private readonly bool _backfillEnabled;
+        private readonly int _backfillLookbackMinutes;
+        private readonly UpdateActivityTally _tally;
+        private readonly Action<string, string, DateTime> _onOsUpdateActivity;
+        private readonly EventRecordWatermark _watermark;
+        private EventLogWatcher _watcher;
+
+        public ServicingTracker(
+            string sessionId,
+            string tenantId,
+            InformationalEventPost post,
+            AgentLogger logger,
+            bool backfillEnabled = true,
+            int backfillLookbackMinutes = 60,
+            string stateDirectory = null,
+            UpdateActivityTally tally = null,
+            Action<string, string, DateTime> onOsUpdateActivity = null)
+        {
+            _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
+            _tenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
+            _post = post ?? throw new ArgumentNullException(nameof(post));
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _backfillEnabled = backfillEnabled;
+            _backfillLookbackMinutes = backfillLookbackMinutes;
+            _tally = tally;
+            _onOsUpdateActivity = onOsUpdateActivity;
+            _watermark = new EventRecordWatermark(stateDirectory, WatermarkStateFileName, logger, "Servicing");
+        }
+
+        public void Start()
+        {
+            _watermark.Load();
+            StartWatcher();
+
+            if (_backfillEnabled && _backfillLookbackMinutes > 0)
+                BackfillRecentEvents();
+            else
+                _logger.Info("Servicing backfill disabled by config");
+        }
+
+        public void Stop()
+        {
+            if (_watcher == null) return;
+            try
+            {
+                _watcher.Enabled = false;
+                _watcher.Dispose();
+                _logger.Info("Servicing watcher stopped");
+            }
+            catch (Exception ex)
+            {
+                _logger.Error("Error stopping Servicing watcher", ex);
+            }
+            finally
+            {
+                _watcher = null;
+            }
+        }
+
+        public void Dispose() => Stop();
+
+        internal void LoadWatermark() => _watermark.Load();
+
+        private static HashSet<int> TargetedSet => new HashSet<int>(TargetedEventIds);
+
+        private void StartWatcher()
+        {
+            try
+            {
+                var query = new EventLogQuery(Channel, PathType.LogName,
+                    WindowsUpdateTracker.BuildXPath(TargetedSet, ProviderName));
+                _watcher = new EventLogWatcher(query);
+                _watcher.EventRecordWritten += OnEventRecordWritten;
+                _watcher.Enabled = true;
+                _logger.Info($"Servicing watcher started: {Channel} ({ProviderName}, targetedIds={string.Join(",", TargetedEventIds)})");
+            }
+            catch (EventLogNotFoundException)
+            {
+                _logger.Warning($"Servicing event log not found: {Channel}");
+            }
+            catch (UnauthorizedAccessException ex)
+            {
+                _logger.Warning($"Servicing watcher access denied for {Channel}: {ex.Message}");
+            }
+            catch (Exception ex)
+            {
+                _logger.Error($"Failed to start Servicing watcher for {Channel}", ex);
+                CollectorDegradationReporter.Report(_post, _sessionId, _tenantId,
+                    collectorName: "ServicingTracker", reason: $"watcher_arm_failed:{Channel}", ex: ex);
+            }
+        }
+
+        private void OnEventRecordWritten(object sender, EventRecordWrittenEventArgs e)
+        {
+            if (e.EventRecord == null) return;
+            try
+            {
+                ProcessRecord(e.EventRecord, isBackfill: false);
+            }
+            catch (Exception ex)
+            {
+                _logger.Error("Error processing Servicing event", ex);
+            }
+        }
+
+        private void ProcessRecord(EventRecord record, bool isBackfill)
+        {
+            var recordId = record.RecordId ?? -1;
+            if (_watermark.IsAlreadyProcessed(recordId)) return;
+
+            string xml = null;
+            try { xml = record.ToXml(); }
+            catch { }
+
+            var fields = ParseUserData(xml);
+            fields.TryGetValue("PackageIdentifier", out var package);
+            fields.TryGetValue("InitialPackageStateTextized", out var initialState);
+            fields.TryGetValue("IntendedPackageStateTextized", out var targetState);
+            fields.TryGetValue("ErrorCode", out var errorCode);
+            fields.TryGetValue("Client", out var client);
+
+            ProcessEvent(
+                eventId: record.Id,
+                recordId: recordId,
+                timeCreatedUtc: record.TimeCreated?.ToUniversalTime(),
+                package: package,
+                initialState: initialState,
+                targetState: targetState,
+                errorCode: errorCode,
+                client: client,
+                isBackfill: isBackfill);
+        }
+
+        /// <summary>Test seam — drives the processing without a Windows-only <see cref="EventRecord"/>.</summary>
+        internal void ProcessEvent(
+            int eventId,
+            long recordId,
+            DateTime? timeCreatedUtc,
+            string package,
+            string initialState,
+            string targetState,
+            string errorCode,
+            string client,
+            bool isBackfill)
+        {
+            if (!_watermark.TryClaim(recordId)) return;
+
+            if (string.IsNullOrEmpty(client) || !OsUpdateClients.Contains(client))
+            {
+                _tally?.Increment($"servicing_other_{eventId}");
+                return;
+            }
+
+            var pkg = string.IsNullOrEmpty(package) ? "(unknown package)" : package;
+            var target = string.IsNullOrEmpty(targetState) ? "?" : targetState;
+
+            string step;
+            string osStep;
+            string message;
+            var severity = EventSeverity.Info;
+            string hresultHex = null;
+            string hresultSymbol = null;
+            if (WindowsUpdateTracker.TryNormalizeHResult(errorCode, out var hresultValue, out var hex) && hresultValue != 0)
+            {
+                hresultHex = hex;
+                hresultSymbol = WindowsUpdateTracker.ResolveHResultSymbol(hresultValue);
+            }
+
+            switch (eventId)
+            {
+                case EventId_InitiatingChanges:
+                    step = "initiating";
+                    osStep = IsState(targetState, "Installed") ? OsUpdateSteps.InstallStarted
+                        : IsState(targetState, "Staged") ? OsUpdateSteps.StagingStarted
+                        : null;
+                    message = $"Servicing started for {pkg}: {(string.IsNullOrEmpty(initialState) ? "?" : initialState)} → {target}";
+                    break;
+                case EventId_StateReached:
+                    step = "state_reached";
+                    osStep = IsState(targetState, "Installed") ? OsUpdateSteps.Installed
+                        : IsState(targetState, "Staged") ? OsUpdateSteps.Staged
+                        : null;
+                    message = $"Servicing finished for {pkg}: now {target}";
+                    break;
+                case EventId_RebootRequired:
+                    step = "reboot_required";
+                    osStep = OsUpdateSteps.RebootRequired;
+                    message = $"Servicing needs a restart to finish {pkg} → {target}";
+                    break;
+                case EventId_ChangeFailed:
+                case EventId_PartiallyInstalled:
+                    step = "failed";
+                    osStep = OsUpdateSteps.Failed;
+                    severity = EventSeverity.Warning;
+                    message = $"Servicing FAILED for {pkg} → {target}" +
+                        (hresultHex != null ? $" ({hresultHex} {hresultSymbol})" : string.Empty) +
+                        (eventId == EventId_PartiallyInstalled ? ", package is partially installed" : string.Empty);
+                    break;
+                default:
+                    return;
+            }
+
+            var data = new Dictionary<string, object>
+            {
+                { "servicingEventId", eventId },
+                { "step", step },
+                { "package", pkg },
+                { "client", client },
+                { "backfilled", isBackfill },
+            };
+            if (!string.IsNullOrEmpty(initialState)) data["initialState"] = initialState;
+            if (!string.IsNullOrEmpty(targetState)) data["targetState"] = targetState;
+            if (hresultHex != null)
+            {
+                data["hresult"] = hresultHex;
+                data["hresultSymbol"] = hresultSymbol;
+            }
+            if (recordId >= 0) data["recordId"] = recordId;
+            if (timeCreatedUtc.HasValue) data["timeCreated"] = timeCreatedUtc.Value.ToString("o");
+
+            _post.Emit(new EnrollmentEvent
+            {
+                SessionId = _sessionId,
+                TenantId = _tenantId,
+                Timestamp = timeCreatedUtc ?? DateTime.UtcNow,
+                EventType = Constants.EventTypes.WindowsUpdateServicing,
+                Severity = severity,
+                Source = Constants.EventSources.ServicingWatcher,
+                Phase = EnrollmentPhase.Unknown,
+                Message = message,
+                Data = data,
+                ImmediateUpload = false,
+            });
+
+            if (osStep != null && _onOsUpdateActivity != null)
+            {
+                try { _onOsUpdateActivity(osStep, pkg, timeCreatedUtc ?? DateTime.UtcNow); }
+                catch (Exception ex) { _logger.Warning($"Servicing: OS update activity callback failed: {ex.Message}"); }
+            }
+
+            // Last: everything this record produced has been handed to the ingress first.
+            _watermark.MarkEmitted(recordId);
+        }
+
+        private static bool IsState(string state, string expected) =>
+            string.Equals(state, expected, StringComparison.OrdinalIgnoreCase);
+
+        /// <summary>
+        /// Child elements of the first element under <c>UserData</c>
+        /// (<c>CbsPackageInitiateChanges</c> / <c>CbsPackageChangeState</c>), keyed by local name,
+        /// case-insensitively. Empty on null/malformed XML — never throws.
+        /// </summary>
+        internal static Dictionary<string, string> ParseUserData(string xml)
+        {
+            var result = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+            if (string.IsNullOrEmpty(xml)) return result;
+
+            try
+            {
+                var doc = XDocument.Parse(xml);
+                var userData = doc.Descendants().FirstOrDefault(e => e.Name.LocalName == "UserData");
+                var payload = userData?.Elements().FirstOrDefault();
+                if (payload == null) return result;
+
+                foreach (var el in payload.Elements())
+                {
+                    if (!result.ContainsKey(el.Name.LocalName))
+                        result[el.Name.LocalName] = el.Value;
+                }
+            }
+            catch
+            {
+                // Malformed / unexpected XML — best effort.
+            }
+
+            return result;
+        }
+
+        private void BackfillRecentEvents()
+        {
+            try
+            {
+                var lookbackMs = (long)_backfillLookbackMinutes * 60 * 1000;
+                var xpath = WindowsUpdateTracker.BuildXPath(TargetedSet, ProviderName, lookbackMs);
+                _logger.Info($"Servicing backfill: scanning {Channel} (lookback={_backfillLookbackMinutes}min, restartWatermark={_watermark.RestartWatermark})");
+
+                int processed = 0;
+                using (var reader = new EventLogReader(new EventLogQuery(Channel, PathType.LogName, xpath)))
+                {
+                    EventRecord record;
+                    while ((record = reader.ReadEvent()) != null)
+                    {
+                        using (record)
+                        {
+                            ProcessRecord(record, isBackfill: true);
+                            processed++;
+                        }
+                    }
+                }
+
+                if (processed > 0)
+                    _logger.Info($"Servicing backfill: scanned {processed} event(s)");
+            }
+            catch (EventLogNotFoundException)
+            {
+                _logger.Warning($"Servicing event log not found during backfill: {Channel}");
+            }
+            catch (UnauthorizedAccessException ex)
+            {
+                _logger.Warning($"Servicing backfill access denied: {ex.Message}");
+            }
+            catch (Exception ex)
+            {
+                _logger.Warning($"Servicing backfill failed: {ex.Message}");
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/ShellCoreTracker.cs

@@ -1,7 +1,9 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.Eventing.Reader;
+using System.Globalization;
 using System.Text.RegularExpressions;
+using System.Threading;
 using AutopilotMonitor.Agent.V2.Core.Logging;
 using AutopilotMonitor.Agent.V2.Core.Orchestration;
 using AutopilotMonitor.Shared;
@@ -31,9 +33,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
     {
         internal const string ShellCoreEventLogChannel = "Microsoft-Windows-Shell-Core/Operational";
         internal const int EventId_ShellCore_WebAppStarted = 62404;
+        internal const int EventId_ShellCore_WebAppStopped = 62405;
+        internal const int EventId_ShellCore_WebAppEventName = 62406;
         internal const int EventId_ShellCore_WebAppEvent = 62407;
         internal const int BackfillLookbackMinutes = 5;
 
+        // 62405 (page stopped) and 62406 (event with a name only) feed the CloudExperienceHost
+        // navigation breadcrumbs in agent.log and the OOBE update page telemetry (D-310), nothing else.
+        private const string WatchedEventIdsXPath =
+            "(EventID=62404 or EventID=62405 or EventID=62406 or EventID=62407)";
+
         /// <summary>
         /// Upper bound for the caller-supplied backfill lookback. Matches the agent's max
         /// lifetime (360 min) — a window wider than the agent can ever live would only widen
@@ -42,25 +51,66 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// </summary>
         internal const int BackfillLookbackMaxMinutes = 360;
 
+        /// <summary>
+        /// Lookback of the first run's update page backfill (<see cref="BackfillUpdatePageTelemetry"/>)
+        /// — the hour the servicing watcher reads back, so the page's records and the update's
+        /// servicing steps cover the same time.
+        /// </summary>
+        internal const int UpdatePageBackfillLookbackMinutes = 60;
+
         private static readonly HashSet<int> TrackedShellCoreEventIds = new HashSet<int>
         {
             EventId_ShellCore_WebAppStarted,
+            EventId_ShellCore_WebAppStopped,
+            EventId_ShellCore_WebAppEventName,
             EventId_ShellCore_WebAppEvent
         };
 
         private static readonly Regex EspExitingPattern = new Regex(
             @"OOBE_ESP.*Exiting", RegexOptions.IgnoreCase | RegexOptions.Compiled);
 
+        // Manifest templates: 62404 "... started. CXID: '%1'.", 62405 "... stopped. Result: '%1'.",
+        // 62406 "... Event 1. Name: '%1'.", 62407 "... Event 2. Name: '%1', Value: '%2'.". The
+        // fields are read from the event PROPERTIES (%1/%2): the formatted message is localized
+        // ("Ergebnis: '…'", "Nom : « … »"), so these patterns are only the fallback for a record
+        // without properties and accept « » and a space before the colon. A 62407 value can carry
+        // URLs with tenant ids — a value leaves the tracker only in a form that cannot
+        // (SafeValuePattern: a boolean, an integer, an HRESULT).
+        private static readonly Regex CxidPattern = new Regex(
+            @"CXID\s*:\s*['\u00AB]\s*([^'\u00BB]*?)\s*['\u00BB]", RegexOptions.CultureInvariant | RegexOptions.Compiled, TimeSpan.FromMilliseconds(100));
+        private static readonly Regex ResultPattern = new Regex(
+            @"Result\s*:\s*['\u00AB]\s*([^'\u00BB]*?)\s*['\u00BB]", RegexOptions.CultureInvariant | RegexOptions.Compiled, TimeSpan.FromMilliseconds(100));
+        private static readonly Regex NamePattern = new Regex(
+            @"Name\s*:\s*['\u00AB]\s*([^'\u00BB]*?)\s*['\u00BB]", RegexOptions.CultureInvariant | RegexOptions.Compiled, TimeSpan.FromMilliseconds(100));
+        private static readonly Regex ValuePattern = new Regex(
+            @"Value\s*:\s*['\u00AB]\s*([^'\u00BB]*?)\s*['\u00BB]", RegexOptions.CultureInvariant | RegexOptions.Compiled, TimeSpan.FromMilliseconds(100));
+        private static readonly Regex SafeValuePattern = new Regex(
+            @"^(?:true|false|-?[0-9]{1,10}|0x[0-9a-f]{1,8})$",
+            RegexOptions.CultureInvariant | RegexOptions.IgnoreCase | RegexOptions.Compiled, TimeSpan.FromMilliseconds(100));
+        private const int MaxBreadcrumbTokenLength = 128;
+
         private readonly AgentLogger _logger;
         private readonly string _sessionId;
         private readonly string _tenantId;
         private readonly InformationalEventPost _post;
         private readonly HelloTracker _helloTracker;
+        private readonly OobeUpdateTelemetry _oobeUpdate;
+        // Shell-Core RecordIds of the update-page records already reported: the restart backfill
+        // must not report a record an earlier run already sent (D-310 field data: the same 20
+        // records came twice after a restart).
+        private readonly EventRecordWatermark _pageWatermark;
+        internal const string PageWatermarkStateFileName = "shellcore-page-watermark.json";
 
         private EventLogWatcher _watcher;
+        private int _started;
+        private int _stopReported;
         private bool _espExitDetected;
         private bool _whiteGloveDetected;
         private bool _helloWizardStartDetected;
+        // 62405 names no page, it ends the last one started. The live watcher's page; a backfill
+        // moves it only with a newer record (see ObserveCxhRecord).
+        private string _lastCxhPage;
+        private long _lastCxhPageRecordId = -1;
         private readonly object _stateLock = new object();
 
         /// <summary>
@@ -99,26 +149,43 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             string tenantId,
             InformationalEventPost post,
             AgentLogger logger,
-            HelloTracker helloTracker)
+            HelloTracker helloTracker,
+            Func<IReadOnlyList<OobeUpdateRegistrySnapshot.KeyState>> oobeUpdateRegistryReader = null,
+            string stateDirectory = null)
         {
             _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
             _tenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
             _post = post ?? throw new ArgumentNullException(nameof(post));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
             _helloTracker = helloTracker; // nullable — HelloTracker may be unavailable in some test setups
+            // Test seam: a fake registry reader; production reads the real registry.
+            _oobeUpdate = new OobeUpdateTelemetry(sessionId, tenantId, post, logger,
+                oobeUpdateRegistryReader ?? OobeUpdateRegistrySnapshot.Read);
+            _pageWatermark = new EventRecordWatermark(stateDirectory, PageWatermarkStateFileName, logger, "Shell-Core update page");
         }
 
         internal bool IsEspExitedForTest { get { lock (_stateLock) { return _espExitDetected; } } }
         internal bool IsWhiteGloveDetectedForTest { get { lock (_stateLock) { return _whiteGloveDetected; } } }
 
+        /// <summary>Loads the update-page watermark as <see cref="Start"/> does, without arming the watcher.</summary>
+        internal void LoadPageWatermark() => _pageWatermark.Load();
+
         public void Start()
         {
+            // The OOBE update registry state at every agent start — so also right after the
+            // update's restart (D-310).
+            if (Interlocked.Exchange(ref _started, 1) == 0)
+            {
+                _oobeUpdate.ReportState(OobeUpdateTelemetry.Moments.AgentStart);
+                _pageWatermark.Load();
+            }
+
             try
             {
                 var query = new EventLogQuery(
                     ShellCoreEventLogChannel,
                     PathType.LogName,
-                    "*[System[(EventID=62404 or EventID=62407)]]");
+                    $"*[System[{WatchedEventIdsXPath}]]");
 
                 _watcher = new EventLogWatcher(query);
                 _watcher.EventRecordWritten += OnEventRecordWritten;
@@ -137,12 +204,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 // WhiteGlove success — indistinguishable on the backend from a real no-signal
                 // enrollment. Surface it as one-shot telemetry.
                 CollectorDegradationReporter.Report(_post, _sessionId, _tenantId,
-                    collectorName: "ShellCoreTracker", reason: "watcher_arm_failed", ex: ex);
+                    collectorName: Constants.EventSources.ShellCoreTracker, reason: "watcher_arm_failed", ex: ex);
             }
         }
 
         public void Stop()
         {
+            // Stop runs again from Dispose — one snapshot, and only for a tracker that started.
+            if (Volatile.Read(ref _started) == 1 && Interlocked.Exchange(ref _stopReported, 1) == 0)
+            {
+                _oobeUpdate.ReportState(OobeUpdateTelemetry.Moments.AgentStop);
+            }
+
             if (_watcher == null) return;
             try
             {
@@ -172,7 +245,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 var description = record.FormatDescription() ?? $"Event ID {record.Id}";
                 var timestamp = (record.TimeCreated ?? DateTime.UtcNow).ToUniversalTime();
 
-                ProcessEvent(record.Id, description, timestamp, record.ProviderName ?? "", isBackfill: false);
+                ProcessEvent(record.Id, description, timestamp, record.ProviderName ?? "", isBackfill: false,
+                    recordId: record.RecordId ?? -1, properties: ReadProperties(record));
             }
             catch (Exception ex)
             {
@@ -184,8 +258,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// Core event-processing logic. Exposed as internal so tests can drive it without
         /// needing to synthesize an <see cref="EventRecord"/> (abstract + Windows-only).
         /// </summary>
-        internal void ProcessEvent(int eventId, string description, DateTime timestamp, string providerName, bool isBackfill)
+        internal void ProcessEvent(
+            int eventId,
+            string description,
+            DateTime timestamp,
+            string providerName,
+            bool isBackfill,
+            long recordId = -1,
+            IReadOnlyList<string> properties = null)
         {
+            var fields = ReadCxhFields(eventId, description, properties);
+            ObserveCxhRecord(eventId, fields, timestamp, isBackfill, recordId, backfillPage: null);
+            if (eventId == EventId_ShellCore_WebAppStopped || eventId == EventId_ShellCore_WebAppEventName) return;
+
             string eventType;
             EventSeverity severity = EventSeverity.Info;
             string message;
@@ -197,7 +282,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             switch (eventId)
             {
                 case EventId_ShellCore_WebAppStarted: // 62404
-                    if (description.Contains("AADHello") || description.Contains("'NGC'"))
+                    if (IsHelloWizardStart(fields.Primary, description))
                     {
                         eventType = Constants.EventTypes.HelloWizardStarted;
                         message = "Windows Hello wizard started (CloudExperienceHost)";
@@ -384,30 +469,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         {
             try
             {
-                var lookbackMs = ClampLookbackMinutes(lookbackMinutes) * 60 * 1000;
-                var query = new EventLogQuery(
-                    ShellCoreEventLogChannel,
-                    PathType.LogName,
-                    $"*[System[(EventID=62404 or EventID=62407) and TimeCreated[timediff(@SystemTime) <= {lookbackMs}]]]");
-
-                var records = new List<(int Id, string Description, DateTime OccurredAtUtc)>();
-                using (var reader = new EventLogReader(query))
-                {
-                    for (EventRecord record = reader.ReadEvent(); record != null; record = reader.ReadEvent())
-                    {
-                        using (record)
-                        {
-                            var description = record.FormatDescription() ?? "";
-                            // Preserve the historical event time across backfill so subscribers
-                            // (EspAndHelloTrackerAdapter) can stamp signals with the source time
-                            // rather than collapsing to wall-clock-now.
-                            var timestamp = (record.TimeCreated ?? DateTime.UtcNow).ToUniversalTime();
-                            records.Add((record.Id, description, timestamp));
-                        }
-                    }
-                }
-
-                ReplayBackfillRecords(records);
+                ReplayBackfillRecords(ReadRecentRecords(lookbackMinutes));
             }
             catch (Exception ex)
             {
@@ -415,6 +477,76 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             }
         }
 
+        /// <summary>
+        /// The FIRST run's counterpart of the restart replay, for telemetry only: the update
+        /// page's records of the last <paramref name="lookbackMinutes"/> minutes (clamped like
+        /// the replay) become <c>oobe_update_page</c> rows. The agent is installed during the ESP
+        /// and can start after the update page began; without this its time attribution has no
+        /// page start to begin the update with (field: a first run 7 min after the update's
+        /// restart saw neither the page start nor the update's first half).
+        /// <para>
+        /// Nothing else is looked at: no Hello-wizard replay, no ESP exit or failure count, no
+        /// <c>agent_trace</c>. The first run keeps its decision behaviour exactly — see
+        /// <see cref="ReplayBackfillRecords"/> for why no replayed record may reach the engine and
+        /// <c>DefaultComponentFactory.ResolveEspExitBackfillLookbackMinutes</c> for why the first
+        /// run has no replay. No boot bound: an agent that first starts after the update's restart
+        /// is exactly the case to cover; the RecordId watermark keeps it from re-sending.
+        /// </para>
+        /// </summary>
+        public void BackfillUpdatePageTelemetry(int lookbackMinutes)
+        {
+            try
+            {
+                ReplayUpdatePageTelemetry(ReadRecentRecords(lookbackMinutes));
+            }
+            catch (Exception ex)
+            {
+                _logger.Warning($"Shell-Core update page backfill failed: {ex.Message}");
+            }
+        }
+
+        /// <summary>The update page telemetry of a chronological batch of Shell-Core records — nothing else.</summary>
+        internal void ReplayUpdatePageTelemetry(IReadOnlyList<ShellCoreRecord> records)
+        {
+            if (records == null || records.Count == 0) return;
+
+            var page = new BackfillPageCursor();
+            foreach (var record in records)
+            {
+                var fields = ReadCxhFields(record.Id, record.Description ?? string.Empty, record.Properties);
+                ObserveCxhRecord(record.Id, fields, record.OccurredAtUtc, isBackfill: true, recordId: record.RecordId, backfillPage: page);
+            }
+        }
+
+        /// <summary>The watched Shell-Core records of the last minutes, oldest first, with their original event time.</summary>
+        private List<ShellCoreRecord> ReadRecentRecords(int lookbackMinutes)
+        {
+            var lookbackMs = ClampLookbackMinutes(lookbackMinutes) * 60 * 1000;
+            var query = new EventLogQuery(
+                ShellCoreEventLogChannel,
+                PathType.LogName,
+                $"*[System[{WatchedEventIdsXPath} and TimeCreated[timediff(@SystemTime) <= {lookbackMs}]]]");
+
+            var records = new List<ShellCoreRecord>();
+            using (var reader = new EventLogReader(query))
+            {
+                for (EventRecord record = reader.ReadEvent(); record != null; record = reader.ReadEvent())
+                {
+                    using (record)
+                    {
+                        var description = record.FormatDescription() ?? "";
+                        // Preserve the historical event time across backfill so subscribers
+                        // (EspAndHelloTrackerAdapter) can stamp signals with the source time
+                        // rather than collapsing to wall-clock-now.
+                        var timestamp = (record.TimeCreated ?? DateTime.UtcNow).ToUniversalTime();
+                        records.Add(new ShellCoreRecord(record.Id, description, timestamp,
+                            record.RecordId ?? -1, ReadProperties(record)));
+                    }
+                }
+            }
+            return records;
+        }
+
         /// <summary>
         /// Replays a chronological batch of Shell-Core records. <b>Only the Hello-wizard start
         /// (62404) is replayed.</b> ESP exits and ESP failures (62407) are counted and reported,
@@ -455,6 +587,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// </summary>
         internal void ReplayBackfillRecords(
             IReadOnlyList<(int Id, string Description, DateTime OccurredAtUtc)> records)
+        {
+            if (records == null) return;
+            var converted = new List<ShellCoreRecord>(records.Count);
+            foreach (var r in records) converted.Add(new ShellCoreRecord(r.Id, r.Description, r.OccurredAtUtc));
+            ReplayBackfillRecords(converted);
+        }
+
+        internal void ReplayBackfillRecords(IReadOnlyList<ShellCoreRecord> records)
         {
             if (records == null || records.Count == 0) return;
 
@@ -462,17 +602,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             var skippedFailures = 0;
             DateTime? oldestSkipped = null;
             DateTime? newestSkipped = null;
+            var page = new BackfillPageCursor();
 
             foreach (var record in records)
             {
                 var description = record.Description ?? string.Empty;
+                var fields = ReadCxhFields(record.Id, description, record.Properties);
+                ObserveCxhRecord(record.Id, fields, record.OccurredAtUtc, isBackfill: true, recordId: record.RecordId, backfillPage: page);
 
                 if (record.Id == EventId_ShellCore_WebAppStarted)
                 {
-                    HandleBackfillRecord(record.Id, description, record.OccurredAtUtc);
+                    HandleBackfillRecord(record.Id, description, record.OccurredAtUtc, fields.Primary);
                     continue;
                 }
 
+                // 62405/62406 only feed the breadcrumbs and the update page telemetry above.
+                if (record.Id != EventId_ShellCore_WebAppEvent) continue;
+
                 var isFailure = HasEspFailurePattern(description);
                 var isExit = !isFailure && EspExitingPattern.IsMatch(description);
                 if (!isFailure && !isExit) continue;
@@ -505,7 +651,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                     TenantId = _tenantId,
                     EventType = Constants.EventTypes.AgentTrace,
                     Severity = EventSeverity.Info,
-                    Source = "ShellCoreTracker",
+                    Source = Constants.EventSources.ShellCoreTracker,
                     Phase = EnrollmentPhase.Unknown,
                     Message =
                         $"Shell-Core replay skipped {skippedExits} ESP exit(s) and {skippedFailures} ESP failure(s) " +
@@ -535,7 +681,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// (<c>record.TimeCreated</c>); subscribers read it via
         /// <see cref="LastEventOccurredAtUtc"/> during their synchronous event handler.
         /// </summary>
-        internal void HandleBackfillRecord(int eventId, string description, DateTime occurredAtUtc)
+        internal void HandleBackfillRecord(int eventId, string description, DateTime occurredAtUtc, string cxid = null)
         {
             if (eventId == EventId_ShellCore_WebAppStarted)
             {
@@ -543,7 +689,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 // are unrelated. Fire-once so a replayed log tail cannot re-raise (downstream is
                 // idempotent anyway: HelloTracker once-guard, adapter dedup flag, engine
                 // set-once fact — this guard just keeps the noise down).
-                if (!description.Contains("AADHello") && !description.Contains("'NGC'")) return;
+                if (!IsHelloWizardStart(cxid ?? ReadCxhFields(eventId, description, null).Primary, description)) return;
 
                 bool shouldRaiseWizard;
                 lock (_stateLock)
@@ -569,6 +715,263 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
         }
 
+        // =====================================================================
+        // CloudExperienceHost navigation: breadcrumbs and OOBE update page telemetry (D-310)
+        // =====================================================================
+
+        /// <summary>The last page started within one backfill batch.</summary>
+        private sealed class BackfillPageCursor
+        {
+            public string Page;
+        }
+
+        /// <summary>
+        /// Writes one agent.log line per CloudExperienceHost page start/stop and per update-page
+        /// event name, so a diagnostics package shows the OOBE navigation. Records of the update
+        /// page itself (<c>OobeNDUP</c>, <c>RebootNDUP</c> and its <c>ExpeditedUpdate_*</c> names)
+        /// are also reported as <c>oobe_update_page</c> — once across agent runs, by RecordId — and
+        /// at the page's live start and stop the registry state behind it as
+        /// <c>oobe_update_state</c>. No decision.
+        /// <para>
+        /// A stop (62405) belongs to the page started last. A backfill batch
+        /// (<paramref name="backfillPage"/>) reads records older than the live watcher's, which is
+        /// armed first, so it keeps its own last page; it moves the live watcher's only with a
+        /// record of a higher RecordId — a replayed older start must not take over the next live
+        /// stop, and a first run's live stop still finds the page that started before the agent.
+        /// </para>
+        /// </summary>
+        private void ObserveCxhRecord(int eventId, CxhFields fields, DateTime occurredAtUtc, bool isBackfill, long recordId,
+            BackfillPageCursor backfillPage)
+        {
+            try
+            {
+                string page;
+                lock (_stateLock)
+                {
+                    if (eventId == EventId_ShellCore_WebAppStarted && fields.Primary != null)
+                    {
+                        if (backfillPage != null) backfillPage.Page = fields.Primary;
+                        if (backfillPage == null || (recordId >= 0 && recordId > _lastCxhPageRecordId))
+                        {
+                            _lastCxhPage = fields.Primary;
+                            if (recordId >= 0) _lastCxhPageRecordId = recordId;
+                        }
+                    }
+                    page = backfillPage != null ? backfillPage.Page : _lastCxhPage;
+                }
+
+                var crumb = FormatCxhBreadcrumb(eventId, fields, page);
+                if (crumb == null) return;
+                _logger.Info(isBackfill ? $"{crumb} (backfill, at {occurredAtUtc:o})" : crumb);
+
+                var record = ParseUpdatePageRecord(eventId, fields, page);
+                if (record == null) return;
+                // A record an earlier run (or this one) already reported — the restart backfill
+                // re-reads the minutes before the restart.
+                if (!_pageWatermark.TryClaim(recordId)) return;
+
+                // Only a reported record moves the state file — at most the run budget plus the
+                // page boundaries; one over the budget stays claimed for this run only.
+                if (_oobeUpdate.ReportPage(record, occurredAtUtc, isBackfill))
+                    _pageWatermark.MarkEmitted(recordId);
+
+                // The registry is read now — only a live page boundary is the page's moment.
+                if (!isBackfill && record.CxhEvent != OobeUpdatePageRecord.EventName)
+                {
+                    _oobeUpdate.ReportState(
+                        record.CxhEvent == OobeUpdatePageRecord.PageStarted
+                            ? OobeUpdateTelemetry.Moments.UpdatePageStarted
+                            : OobeUpdateTelemetry.Moments.UpdatePageStopped,
+                        record.Page);
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.Debug($"ShellCoreTracker: CXH record observation failed: {ex.Message}");
+            }
+        }
+
+        /// <summary>The own fields of a CloudExperienceHost record: CXID, result or name (%1) and the 62407 value (%2).</summary>
+        internal readonly struct CxhFields
+        {
+            public CxhFields(string primary, string value)
+            {
+                Primary = primary;
+                Value = value;
+            }
+
+            /// <summary>62404: CXID; 62405: result; 62406/62407: event name. Null when not readable.</summary>
+            public string Primary { get; }
+
+            /// <summary>62407: the raw value (never logged or sent unless it is of a safe form).</summary>
+            public string Value { get; }
+        }
+
+        /// <summary>
+        /// The record's fields from its event properties, which carry them verbatim in every
+        /// display language. Without properties (a test, a record that failed to render them) the
+        /// formatted message is parsed — English punctuation and « » only, so a localized label
+        /// ("Ergebnis", "Nom") yields null there.
+        /// </summary>
+        internal static CxhFields ReadCxhFields(int eventId, string description, IReadOnlyList<string> properties)
+        {
+            if (properties != null && properties.Count > 0)
+            {
+                return new CxhFields(
+                    Bound(properties[0]),
+                    eventId == EventId_ShellCore_WebAppEvent && properties.Count > 1 ? Bound(properties[1]) : null);
+            }
+
+            switch (eventId)
+            {
+                case EventId_ShellCore_WebAppStarted:
+                    return new CxhFields(ExtractToken(CxidPattern, description), null);
+                case EventId_ShellCore_WebAppStopped:
+                    return new CxhFields(ExtractToken(ResultPattern, description), null);
+                case EventId_ShellCore_WebAppEventName:
+                    return new CxhFields(ExtractToken(NamePattern, description), null);
+                case EventId_ShellCore_WebAppEvent:
+                    return new CxhFields(ExtractToken(NamePattern, description), ExtractToken(ValuePattern, description));
+                default:
+                    return default;
+            }
+        }
+
+        /// <summary>
+        /// The breadcrumb for one Shell-Core record, or null when it is not one: a page start
+        /// (62404, its CXID), a page stop (62405, its result, attributed to the last started
+        /// page), or an update-page event name (62406/62407 — a 62407 value only in a safe form).
+        /// </summary>
+        internal static string FormatCxhBreadcrumb(int eventId, string description, string lastPage) =>
+            FormatCxhBreadcrumb(eventId, ReadCxhFields(eventId, description, null), lastPage);
+
+        internal static string FormatCxhBreadcrumb(int eventId, CxhFields fields, string lastPage)
+        {
+            switch (eventId)
+            {
+                case EventId_ShellCore_WebAppStarted:
+                    return fields.Primary == null ? null : $"CXH page started: {fields.Primary}";
+                case EventId_ShellCore_WebAppStopped:
+                    return $"CXH page stopped: {lastPage ?? "?"} (result={fields.Primary ?? "?"})";
+                case EventId_ShellCore_WebAppEventName:
+                case EventId_ShellCore_WebAppEvent:
+                {
+                    if (!IsUpdatePageToken(fields.Primary)) return null;
+                    var value = eventId == EventId_ShellCore_WebAppEvent ? SafeValue(fields.Value) : null;
+                    return value == null ? $"CXH event: {fields.Primary}" : $"CXH event: {fields.Primary} (value={value})";
+                }
+                default:
+                    return null;
+            }
+        }
+
+        /// <summary>
+        /// The record of the OOBE update page, or null for any other CloudExperienceHost record:
+        /// the start of a page whose CXID names NDUP, the stop of such a page (62405, attributed
+        /// to the last started page), or an update-page event name from 62406/62407.
+        /// </summary>
+        internal static OobeUpdatePageRecord ParseUpdatePageRecord(int eventId, string description, string lastPage) =>
+            ParseUpdatePageRecord(eventId, ReadCxhFields(eventId, description, null), lastPage);
+
+        internal static OobeUpdatePageRecord ParseUpdatePageRecord(int eventId, CxhFields fields, string lastPage)
+        {
+            switch (eventId)
+            {
+                case EventId_ShellCore_WebAppStarted:
+                    return IsUpdatePageToken(fields.Primary)
+                        ? new OobeUpdatePageRecord(OobeUpdatePageRecord.PageStarted, eventId, page: fields.Primary)
+                        : null;
+                case EventId_ShellCore_WebAppStopped:
+                    return IsUpdatePageToken(lastPage)
+                        ? new OobeUpdatePageRecord(OobeUpdatePageRecord.PageStopped, eventId,
+                            page: lastPage, result: fields.Primary ?? "?")
+                        : null;
+                case EventId_ShellCore_WebAppEventName:
+                case EventId_ShellCore_WebAppEvent:
+                {
+                    if (!IsUpdatePageToken(fields.Primary)) return null;
+                    var value = eventId == EventId_ShellCore_WebAppEvent ? SafeValue(fields.Value) : null;
+                    return new OobeUpdatePageRecord(OobeUpdatePageRecord.EventName, eventId, name: fields.Primary, value: value);
+                }
+                default:
+                    return null;
+            }
+        }
+
+        internal static bool IsUpdatePageToken(string token) =>
+            token != null
+            && (token.IndexOf("NDUP", StringComparison.OrdinalIgnoreCase) >= 0
+                || token.IndexOf("ExpeditedUpdate", StringComparison.OrdinalIgnoreCase) >= 0);
+
+        /// <summary>
+        /// The Hello wizard's CloudExperienceHost start: CXID <c>AADHello</c> or <c>NGC</c>. With
+        /// no readable CXID the formatted message decides, as before (an English or German
+        /// message quotes the CXID as <c>'NGC'</c>).
+        /// </summary>
+        internal static bool IsHelloWizardStart(string cxid, string description) =>
+            cxid != null
+                ? cxid.Contains("AADHello") || string.Equals(cxid, "NGC", StringComparison.Ordinal)
+                : description != null && (description.Contains("AADHello") || description.Contains("'NGC'"));
+
+        /// <summary>
+        /// The 62407 value when it is a boolean, an integer of up to ten digits or an HRESULT —
+        /// forms that cannot carry a URL or a tenant id (the CSP gate, error codes). Null for
+        /// anything else.
+        /// </summary>
+        internal static string ExtractSafeValue(string description) =>
+            SafeValue(ReadCxhFields(EventId_ShellCore_WebAppEvent, description, null).Value);
+
+        internal static string SafeValue(string value)
+        {
+            if (string.IsNullOrEmpty(value)) return null;
+            try
+            {
+                return SafeValuePattern.IsMatch(value) ? value : null;
+            }
+            catch (RegexMatchTimeoutException)
+            {
+                return null;
+            }
+        }
+
+        private static string ExtractToken(Regex pattern, string description)
+        {
+            if (string.IsNullOrEmpty(description)) return null;
+            try
+            {
+                var match = pattern.Match(description);
+                return match.Success ? Bound(match.Groups[1].Value) : null;
+            }
+            catch (RegexMatchTimeoutException)
+            {
+                return null;
+            }
+        }
+
+        private static string Bound(string token)
+        {
+            if (string.IsNullOrEmpty(token)) return null;
+            return token.Length > MaxBreadcrumbTokenLength ? token.Substring(0, MaxBreadcrumbTokenLength) + "…" : token;
+        }
+
+        /// <summary>The event's property values as strings (the manifest's %1, %2, …); null when unreadable.</summary>
+        private static IReadOnlyList<string> ReadProperties(EventRecord record)
+        {
+            try
+            {
+                var properties = record.Properties;
+                if (properties == null || properties.Count == 0) return null;
+                var values = new string[properties.Count];
+                for (var i = 0; i < properties.Count; i++)
+                    values[i] = Convert.ToString(properties[i]?.Value, CultureInfo.InvariantCulture);
+                return values;
+            }
+            catch (Exception)
+            {
+                return null;
+            }
+        }
+
         // =====================================================================
         // Pattern helpers
         // =====================================================================
@@ -608,4 +1011,27 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             return "Unknown_ESP_Failure";
         }
     }
+
+    /// <summary>One Shell-Core record read by the restart backfill.</summary>
+    internal readonly struct ShellCoreRecord
+    {
+        public ShellCoreRecord(int id, string description, DateTime occurredAtUtc, long recordId = -1, IReadOnlyList<string> properties = null)
+        {
+            Id = id;
+            Description = description;
+            OccurredAtUtc = occurredAtUtc;
+            RecordId = recordId;
+            Properties = properties;
+        }
+
+        public int Id { get; }
+        public string Description { get; }
+        public DateTime OccurredAtUtc { get; }
+
+        /// <summary>The channel's RecordId; -1 when unknown (no cross-run dedup).</summary>
+        public long RecordId { get; }
+
+        /// <summary>The event's property values (%1, %2, …); null when unknown.</summary>
+        public IReadOnlyList<string> Properties { get; }
+    }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/StallProbeCollector.cs

@@ -39,7 +39,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
     ///   - Trace-indexed probes: emit a <c>stall_probe_check</c> Trace event on quiet/activeInstalls.
     ///   - Non-trace probes: emit nothing when no anomaly is found (agent log only).
     ///   - Anomaly found: always emit <c>stall_probe_result</c> Warning (plus EspFailureDetected if terminal).
-    ///   - Probe index configured as "session-stalled": emit fire-once <c>session_stalled</c> Warning.
+    ///   - Probe index configured as "session-stalled": emit fire-once <c>session_stalled</c> Warning
+    ///     (held back while a tenant-extended Hello wait is pending, emitted once it is over).
     /// </summary>
     public class StallProbeCollector
     {
@@ -54,10 +55,20 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         private readonly HashSet<int> _harmlessModernDeploymentEventIds;
         private readonly bool _isDevicePreparation;
 
+        // True while a tenant-extended Hello wait (up to 60 min) is pending in the decision
+        // engine. It is a bounded wait that resolves the session either way — not a stall — so
+        // session_stalled is held back until it is over.
+        private readonly Func<bool> _helloWaitPending;
+
         private readonly object _stateLock = new object();
         private readonly HashSet<int> _firedProbeIndices = new HashSet<int>();
         private bool _sessionStalledFired;
 
+        // The session_stalled report held back while the Hello wait was pending (the probe result
+        // of that idle window). Emitted on a later tick once the wait is over and the session is
+        // still idle; dropped by real activity (ResetProbes).
+        private ProbeResult _deferredSessionStalled;
+
         // P2 — monotonic generation, bumped by ResetProbes. RunProbe runs OUTSIDE _stateLock; if a
         // real-activity reset lands while a probe is in flight, the post-probe "mark fired" must be
         // dropped (its generation is stale) so the next idle period can fire that probe again.
@@ -153,9 +164,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             string[] sources,
             int sessionStalledAfterProbeIndex,
             int[] harmlessModernDeploymentEventIds = null,
-            bool isDevicePreparation = false)
+            bool isDevicePreparation = false,
+            Func<bool> helloWaitPending = null)
         {
             _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
+            _helloWaitPending = helloWaitPending;
             _tenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
             _post = post ?? throw new ArgumentNullException(nameof(post));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
@@ -192,6 +205,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 // Always bump the generation, even when no probes are currently marked fired — a
                 // probe may be running right now (outside the lock) and must not re-mark itself.
                 _probeGeneration++;
+                _deferredSessionStalled = null;
                 if (_firedProbeIndices.Count > 0)
                 {
                     _logger.Trace($"StallProbeCollector: resetting {_firedProbeIndices.Count} fired probes");
@@ -206,6 +220,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// </summary>
         public void CheckAndRunProbes(double idleMinutes)
         {
+            EmitDeferredSessionStalledIfDue(idleMinutes);
+
             // Iterate thresholds from lowest to highest so probes fire in order.
             for (int i = 0; i < _thresholdsMinutes.Length; i++)
             {
@@ -225,7 +241,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 if (alreadyFired)
                     continue;
 
-                RunProbe(probeIndex, thresholdMinutes, idleMinutes);
+                RunProbe(probeIndex, thresholdMinutes, idleMinutes, genAtStart);
 
                 lock (_stateLock)
                 {
@@ -237,7 +253,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             }
         }
 
-        private void RunProbe(int probeIndex, int thresholdMinutes, double idleMinutes)
+        private void RunProbe(int probeIndex, int thresholdMinutes, double idleMinutes, int generation)
         {
             var started = DateTime.UtcNow;
             var result = new ProbeResult { ProbeIndex = probeIndex, IdleMinutes = Math.Round(idleMinutes, 1) };
@@ -293,8 +309,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
             // session_stalled is fire-once across the whole session. It fires at the configured
             // probe index UNLESS activeInstalls is observed (activeInstalls counts as progress).
+            // While a tenant Hello wait is pending it is held back, not dropped.
             if (probeIndex == _sessionStalledAfterProbeIndex && !hasActiveInstalls)
             {
+                if (IsHelloWaitPending())
+                {
+                    lock (_stateLock)
+                    {
+                        // P2: a reset that landed while this probe ran ended the idle window.
+                        if (!_sessionStalledFired && _probeGeneration == generation)
+                            _deferredSessionStalled = result;
+                    }
+                    _logger.Info($"StallProbeCollector: session_stalled held back at probe {probeIndex} — a tenant Hello wait is still pending");
+                    return;
+                }
+
                 lock (_stateLock)
                 {
                     if (_sessionStalledFired)
@@ -305,6 +334,52 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             }
         }
 
+        /// <summary>
+        /// Emits the held-back session_stalled report once the Hello wait is over and the session
+        /// is still idle (no ResetProbes since), with the idle time of this tick.
+        /// </summary>
+        private void EmitDeferredSessionStalledIfDue(double idleMinutes)
+        {
+            ProbeResult deferred;
+            lock (_stateLock)
+            {
+                deferred = _deferredSessionStalled;
+                if (deferred == null || _sessionStalledFired)
+                    return;
+            }
+
+            if (IsHelloWaitPending())
+                return;
+
+            lock (_stateLock)
+            {
+                if (_sessionStalledFired || !ReferenceEquals(_deferredSessionStalled, deferred))
+                    return;
+                _sessionStalledFired = true;
+                _deferredSessionStalled = null;
+            }
+
+            deferred.IdleMinutes = Math.Round(idleMinutes, 1);
+            _logger.Info($"StallProbeCollector: Hello wait over, still idle at {deferred.IdleMinutes}min — emitting the held-back session_stalled");
+            EmitSessionStalledEvent(deferred);
+        }
+
+        private bool IsHelloWaitPending()
+        {
+            if (_helloWaitPending == null)
+                return false;
+            try
+            {
+                return _helloWaitPending();
+            }
+            catch (Exception ex)
+            {
+                // A failing probe must never cost the stall report — treat as not pending.
+                _logger.Warning($"StallProbeCollector: Hello-wait probe threw, treating as not pending: {ex.Message}");
+                return false;
+            }
+        }
+
         private void RunWithTimeout(Action<ProbeResult> scan, int timeoutMs, string sourceName, ProbeResult result)
         {
             // Enforce a real hard timeout: run the source on a dedicated background thread and

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/SystemTimelineTracker.cs

@@ -340,7 +340,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 Timestamp = timeCreatedUtc ?? DateTime.UtcNow,
                 EventType = Constants.EventTypes.SystemClockChanged,
                 Severity = isLargeStep ? EventSeverity.Warning : EventSeverity.Info,
-                Source = "SystemTimelineWatcher",
+                Source = Constants.EventSources.SystemTimelineWatcher,
                 Phase = EnrollmentPhase.Unknown,
                 Message = message,
                 Data = data,
@@ -467,7 +467,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 Timestamp = timeCreatedUtc ?? DateTime.UtcNow,
                 EventType = Constants.EventTypes.SystemSleepEpisode,
                 Severity = EventSeverity.Info,
-                Source = "SystemTimelineWatcher",
+                Source = Constants.EventSources.SystemTimelineWatcher,
                 Phase = EnrollmentPhase.Unknown,
                 Message = message,
                 Data = data,

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/UpdateActivityTally.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
+{
+    /// <summary>
+    /// Thread-safe counters for update activity that is counted instead of emitted (D-310): Store,
+    /// Defender and other non-OS update events, repeated scan results, servicing steps of non-OS
+    /// packages. Shared by the update watchers of one host, which reports the totals once as
+    /// <c>windows_update_activity_summary</c> when it stops.
+    /// </summary>
+    internal sealed class UpdateActivityTally
+    {
+        private readonly object _lock = new object();
+        private readonly Dictionary<string, int> _counts = new Dictionary<string, int>(StringComparer.Ordinal);
+
+        public void Increment(string key)
+        {
+            if (string.IsNullOrEmpty(key)) return;
+            lock (_lock)
+            {
+                _counts.TryGetValue(key, out var current);
+                _counts[key] = current + 1;
+            }
+        }
+
+        public bool IsEmpty
+        {
+            get { lock (_lock) return _counts.Count == 0; }
+        }
+
+        /// <summary>Counts ordered by key, for a stable event payload.</summary>
+        public IReadOnlyList<KeyValuePair<string, int>> Snapshot()
+        {
+            lock (_lock)
+            {
+                return _counts.OrderBy(kv => kv.Key, StringComparer.Ordinal).ToList();
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/WindowsUpdateClassifier.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Text.RegularExpressions;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
+{
+    /// <summary>
+    /// Sorts a Windows Update client event into the update class that decides how it is reported
+    /// (D-310). Only <see cref="Os"/> updates — Windows quality/cumulative/servicing-stack/feature
+    /// updates, .NET Framework and the Malicious Software Removal Tool — are enrollment-relevant and
+    /// emitted one by one. Defender intelligence and Store app updates arrive every few minutes on a
+    /// fresh device (up to 171 downloads per hour in the field census) and are only counted.
+    /// </summary>
+    internal static class WindowsUpdateClassifier
+    {
+        public const string Os = "os";
+        public const string Defender = "defender";
+        public const string Store = "store";
+        public const string Other = "other";
+
+        /// <summary>The Microsoft Store service; WU events carry it as <c>serviceGuid</c>.</summary>
+        internal const string StoreServiceGuid = "855e8a7c-ecb4-4ca3-b045-1dfa50104289";
+
+        // Store packages are titled "<12-char product id>-<Publisher.App>", e.g. "9NBLGGH4NNS1-Microsoft.DesktopAppInstaller";
+        // bundles add an "ApplicationSet-" prefix.
+        private static readonly Regex StoreProductTitle =
+            new Regex(@"^(ApplicationSet-)?[0-9A-Z]{12}-\S", RegexOptions.CultureInvariant, TimeSpan.FromMilliseconds(100));
+
+        private static readonly Regex DefenderTitle =
+            new Regex(@"Microsoft Defender|Windows Defender", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant, TimeSpan.FromMilliseconds(100));
+
+        // "Windows" plus "Update"/"Upgrade" covers cumulative, quality, security, servicing-stack,
+        // dynamic and feature updates in both the GA and the Insider title forms.
+        private static readonly Regex WindowsUpdateTitle =
+            new Regex(@"\bWindows\b.*\b(Update|Upgrade)\b|\b(Update|Upgrade)\b.*\bWindows\b",
+                RegexOptions.IgnoreCase | RegexOptions.CultureInvariant, TimeSpan.FromMilliseconds(100));
+
+        private static readonly Regex OsTitleExtras =
+            new Regex(@"\.NET Framework|Servicing Stack|Malicious Software Removal Tool",
+                RegexOptions.IgnoreCase | RegexOptions.CultureInvariant, TimeSpan.FromMilliseconds(100));
+
+        public static string Classify(string updateTitle, string serviceGuid)
+        {
+            if (!string.IsNullOrEmpty(serviceGuid)
+                && serviceGuid.Trim('{', '}', ' ').Equals(StoreServiceGuid, StringComparison.OrdinalIgnoreCase))
+            {
+                return Store;
+            }
+
+            if (string.IsNullOrWhiteSpace(updateTitle)) return Other;
+
+            try
+            {
+                if (StoreProductTitle.IsMatch(updateTitle)) return Store;
+                if (DefenderTitle.IsMatch(updateTitle)) return Defender;
+                if (OsTitleExtras.IsMatch(updateTitle) || WindowsUpdateTitle.IsMatch(updateTitle)) return Os;
+            }
+            catch (RegexMatchTimeoutException)
+            {
+                // A pathological title must never cost the event — it is reported as "other".
+            }
+
+            return Other;
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/WindowsUpdateTracker.cs

@@ -2,100 +2,106 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics.Eventing.Reader;
 using System.Globalization;
-using System.IO;
 using System.Linq;
+using System.Threading;
 using System.Xml.Linq;
 using AutopilotMonitor.Agent.V2.Core.Logging;
 using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.DecisionCore.State;
 using AutopilotMonitor.Shared;
 using AutopilotMonitor.Shared.Models;
 using AutopilotMonitor.Shared.Services;
-using Newtonsoft.Json;
 
 namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 {
     /// <summary>
-    /// Watches <c>Microsoft-Windows-WindowsUpdateClient/Operational</c> for quality/cumulative
-    /// update install activity that happens DURING Autopilot OOBE / ESP and forwards it as
-    /// structured <c>windows_update_succeeded</c> / <c>windows_update_failed</c> /
-    /// <c>windows_update_started</c> events.
+    /// Watches ONE channel of the <c>Microsoft-Windows-WindowsUpdateClient</c> provider for update
+    /// activity during OOBE / ESP and forwards it as <c>windows_update_started</c> /
+    /// <c>windows_update_succeeded</c> / <c>windows_update_failed</c> events.
     /// <para>
-    /// This is a blind spot no other tool surfaces well: a cumulative update installing mid-OOBE
-    /// can break the enrollment (r/Intune KB5095189), and the ESP "Install Windows quality updates
-    /// during OOBE" feature makes it increasingly common. The Intune console shows none of it — it
-    /// is otherwise deep manual digging on the device.
+    /// <b>Two channels (D-310).</b> The provider manifest writes the install events — 19 success,
+    /// 20 failure (HRESULT), 43 install started, 44 download started — to the <b>System</b> log and
+    /// the scan/download events — 25 scan failed, 26 scan found N, 31 download failed, 41
+    /// downloaded — to the Operational channel. The host runs one instance per channel; RecordIds
+    /// are per channel, so each instance keeps its own watermark. The System log is shared with
+    /// every other provider, hence the provider filter in its XPath.
     /// </para>
     /// <para>
-    /// <b>Backfill.</b> OOBE updates run at the early "Getting updates" screen, frequently BEFORE the
-    /// agent starts. The WindowsUpdateClient/Operational .evtx persists across the mid-OOBE reboot,
-    /// so a startup backfill with a generous lookback catches those pre-agent events.
+    /// <b>Classification.</b> Only Windows/.NET updates (<see cref="WindowsUpdateClassifier.Os"/>)
+    /// are emitted one by one and reported to the decision engine. Store, Defender and other
+    /// updates arrive every few minutes on a fresh device and are only counted into the host's
+    /// <see cref="UpdateActivityTally"/>. Repeated scan results (26) and scan failures (25) are
+    /// deduplicated; their repeats are counted the same way.
     /// </para>
     /// <para>
-    /// <b>Cross-restart dedup.</b> Unlike the single-latch WhiteGlove backfill, WU events are many
-    /// distinct records, so an agent restart would re-read (and re-emit) events already reported in
-    /// the prior run. We persist the highest processed <see cref="EventRecord.RecordId"/> as a
-    /// watermark and skip records at/below it. Live records always carry a higher RecordId and pass.
-    /// </para>
-    /// <para>
-    /// <b>Verified EventIDs (build against these):</b> 19=install success, 20=install failure
-    /// (carries HRESULT in <c>errorCode</c>), 43=install started, 44=download started. IDs whose
-    /// semantics are unverified across sources (25/26/31, restart-required 21 vs 41) are excluded by
-    /// default and can be added via <c>CollectorConfiguration.WindowsUpdateTargetedEventIds</c>
-    /// after validation on a real device trace — no redeploy needed.
+    /// <b>Backfill.</b> Updates can start before the agent does; the .evtx survives the reboot, so
+    /// a startup backfill with a generous lookback catches them. Backfilled events keep their own
+    /// event time on the timeline.
     /// </para>
     /// </summary>
     internal sealed class WindowsUpdateTracker : IDisposable
     {
         internal const string Channel = "Microsoft-Windows-WindowsUpdateClient/Operational";
+        internal const string SystemChannel = "System";
+        internal const string ProviderName = "Microsoft-Windows-WindowsUpdateClient";
         internal const string OrchestratorChannel = "Microsoft-Windows-UpdateOrchestrator/Operational";
 
-        internal const int EventId_InstallSuccess  = 19;
-        internal const int EventId_InstallFailure  = 20;
+        // System channel (provider manifest).
+        internal const int EventId_InstallSuccess   = 19;
+        internal const int EventId_InstallFailure   = 20;
         internal const int EventId_InstallStarted   = 43;
         internal const int EventId_DownloadStarted  = 44;
+        // Operational channel.
+        internal const int EventId_ScanFailed       = 25;
+        internal const int EventId_ScanFound        = 26;
+        internal const int EventId_DownloadFailed   = 31;
+        internal const int EventId_Downloaded       = 41;
 
         internal const string WatermarkStateFileName = "windows-update-watermark.json";
+        internal const string SystemWatermarkStateFileName = "windows-update-system-watermark.json";
 
         // Hard bound for the unfiltered census scan — during OOBE both channels carry at most a
         // few hundred records in the lookback window; the cap only guards against a pathological
         // log. A truncated census says so in its payload (no silent caps).
         internal const int CensusRecordCap = 5000;
 
+        // Scan results repeat every few minutes; only changes are worth a timeline row.
+        internal const int MaxScanFoundEmissions = 10;
+        internal const int MaxScanFailedEmissions = 5;
+
+        private static readonly int[] DefaultSystemEventIds = { EventId_InstallSuccess, EventId_InstallFailure, EventId_InstallStarted, EventId_DownloadStarted };
+        private static readonly int[] DefaultOperationalEventIds = { EventId_ScanFailed, EventId_ScanFound, EventId_DownloadFailed, EventId_Downloaded };
+
         private readonly AgentLogger _logger;
         private readonly string _sessionId;
         private readonly string _tenantId;
         private readonly InformationalEventPost _post;
+        private readonly string _channel;
+        private readonly bool _isSystemChannel;
         private readonly HashSet<int> _targetedEventIds;
         private readonly bool _backfillEnabled;
         private readonly int _backfillLookbackMinutes;
-        private readonly string _stateDirectory;
         private readonly bool _channelCensusEnabled;
         private readonly Func<bool> _osBuildChangedProvider;
+        private readonly UpdateActivityTally _tally;
+        private readonly Action<string, string, DateTime> _onOsUpdateActivity;
+        private readonly EventRecordWatermark _watermark;
 
-        // Count of targeted WU events emitted THIS run (live + backfill). Zero after the backfill
-        // while the OS build provably changed = the watcher is blind to the update's channel/IDs.
+        // Targeted events processed THIS run (any class). Zero after the backfill while the OS
+        // build provably changed = the watcher is blind to the update's channel/IDs.
         private int _emittedThisRun;
 
+        private readonly object _throttleLock = new object();
+        private readonly HashSet<string> _scanFailureCodesReported = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        private string _lastScanFoundCount;
+        private int _scanFoundEmitted;
+
         private EventLogWatcher _watcher;
 
-        // Dedup. Guarded because EventRecordWritten callbacks run concurrently with the backfill scan.
-        //
-        // Cross-restart boundary loaded from disk: the highest RecordId emitted in a PRIOR run.
-        // Immutable during this run — events at/below it were already emitted before this process
-        // started and must not be re-emitted by the backfill scan.
-        private long _restartWatermark = -1;
-        // RecordIds emitted in THIS run — the intra-run dedup set. Deliberately a HashSet, NOT a
-        // high-water mark: the live watcher is armed before the backfill runs, so a live event with a
-        // HIGHER RecordId can be processed before/during backfill. A high-water mark would then make
-        // the dedup skip every older, never-emitted backfill event (recordId <= max) — silently
-        // dropping exactly the early pre-agent OOBE updates that are this feature's whole point.
-        // WU install events are low-volume (a handful per enrollment), so the set stays tiny.
-        private readonly HashSet<long> _seenThisRun = new HashSet<long>();
-        // Highest RecordId emitted so far (max of restart watermark + this run). Persisted so the next
-        // run's restart watermark is correct.
-        private long _maxEmittedRecordId = -1;
-        private readonly object _watermarkLock = new object();
-
+        /// <param name="channel">Event log channel; defaults to the Operational channel.</param>
+        /// <param name="targetedEventIds">IDs to watch on <paramref name="channel"/>; defaults to the manifest set of that channel.</param>
+        /// <param name="tally">Counter for activity that is counted instead of emitted; null drops the counts.</param>
+        /// <param name="onOsUpdateActivity">Called for every Windows/.NET update step with (step, update title, event time).</param>
         public WindowsUpdateTracker(
             string sessionId,
             string tenantId,
@@ -106,25 +112,60 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             int backfillLookbackMinutes = 60,
             string stateDirectory = null,
             bool channelCensusEnabled = true,
-            Func<bool> osBuildChangedProvider = null)
+            Func<bool> osBuildChangedProvider = null,
+            string channel = null,
+            UpdateActivityTally tally = null,
+            Action<string, string, DateTime> onOsUpdateActivity = null)
         {
             _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
             _tenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
             _post = post ?? throw new ArgumentNullException(nameof(post));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _channel = string.IsNullOrEmpty(channel) ? Channel : channel;
+            _isSystemChannel = string.Equals(_channel, SystemChannel, StringComparison.OrdinalIgnoreCase);
             _targetedEventIds = targetedEventIds != null && targetedEventIds.Length > 0
                 ? new HashSet<int>(targetedEventIds)
-                : new HashSet<int> { EventId_InstallSuccess, EventId_InstallFailure, EventId_InstallStarted, EventId_DownloadStarted };
+                : new HashSet<int>(_isSystemChannel ? DefaultSystemEventIds : DefaultOperationalEventIds);
             _backfillEnabled = backfillEnabled;
             _backfillLookbackMinutes = backfillLookbackMinutes;
-            _stateDirectory = stateDirectory != null ? Environment.ExpandEnvironmentVariables(stateDirectory) : null;
             _channelCensusEnabled = channelCensusEnabled;
             _osBuildChangedProvider = osBuildChangedProvider;
+            _tally = tally;
+            _onOsUpdateActivity = onOsUpdateActivity;
+            _watermark = new EventRecordWatermark(
+                stateDirectory,
+                _isSystemChannel ? SystemWatermarkStateFileName : WatermarkStateFileName,
+                logger,
+                _isSystemChannel ? "WindowsUpdate (System)" : "WindowsUpdate");
         }
 
+        /// <summary>Channel this instance watches.</summary>
+        internal string WatchedChannel => _channel;
+
+        /// <summary>Targeted events processed this run, any class.</summary>
+        internal int EmittedThisRun => Volatile.Read(ref _emittedThisRun);
+
+        /// <summary>EventIDs this instance watches on <see cref="WatchedChannel"/>.</summary>
+        internal IReadOnlyCollection<int> TargetedEventIds => _targetedEventIds;
+
+        /// <summary>
+        /// True when the provider manifest writes <paramref name="eventId"/> to the System log
+        /// (16–24, 27, 28, 32, 33, 43, 44, 212–218); all other IDs live in the Operational channel.
+        /// </summary>
+        internal static bool IsSystemChannelEventId(int eventId) =>
+            (eventId >= 16 && eventId <= 24)
+            || eventId == 27 || eventId == 28
+            || eventId == 32 || eventId == 33
+            || eventId == 43 || eventId == 44
+            || (eventId >= 212 && eventId <= 218);
+
+        /// <summary>
+        /// Watches the channel and backfills it. The blind-spot census is NOT run here: it needs
+        /// the emissions of every channel, so the host runs it after all its trackers started.
+        /// </summary>
         public void Start()
         {
-            LoadWatermark();
+            _watermark.Load();
             StartWatcher();
 
             if (_backfillEnabled && _backfillLookbackMinutes > 0)
@@ -133,10 +174,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             }
             else
             {
-                _logger.Info("WindowsUpdate backfill disabled by config");
+                _logger.Info($"WindowsUpdate backfill disabled by config ({_channel})");
             }
-
-            EmitChannelCensusIfBlind();
         }
 
         public void Stop()
@@ -146,11 +185,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             {
                 _watcher.Enabled = false;
                 _watcher.Dispose();
-                _logger.Info("WindowsUpdate watcher stopped");
+                _logger.Info($"WindowsUpdate watcher stopped ({_channel})");
             }
             catch (Exception ex)
             {
-                _logger.Error("Error stopping WindowsUpdate watcher", ex);
+                _logger.Error($"Error stopping WindowsUpdate watcher ({_channel})", ex);
             }
             finally
             {
@@ -160,52 +199,64 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
         public void Dispose() => Stop();
 
+        internal void LoadWatermark() => _watermark.Load();
+
         // -----------------------------------------------------------------------
         // Watcher lifecycle
         // -----------------------------------------------------------------------
 
+        private string ProviderFilter => _isSystemChannel ? ProviderName : null;
+
         private void StartWatcher()
         {
             if (_targetedEventIds.Count == 0)
             {
-                _logger.Warning("WindowsUpdate watcher not started: no targeted EventIDs configured");
+                _logger.Warning($"WindowsUpdate watcher not started: no targeted EventIDs configured ({_channel})");
                 return;
             }
 
             try
             {
-                var xpath = BuildXPath(_targetedEventIds);
-                var query = new EventLogQuery(Channel, PathType.LogName, xpath);
+                var query = new EventLogQuery(_channel, PathType.LogName, BuildXPath(_targetedEventIds, ProviderFilter));
                 _watcher = new EventLogWatcher(query);
                 _watcher.EventRecordWritten += OnEventRecordWritten;
                 _watcher.Enabled = true;
-                _logger.Info($"WindowsUpdate watcher started: {Channel} (targetedIds={_targetedEventIds.Count})");
+                _logger.Info($"WindowsUpdate watcher started: {_channel} (targetedIds={string.Join(",", _targetedEventIds.OrderBy(id => id))})");
             }
             catch (EventLogNotFoundException)
             {
-                _logger.Warning($"WindowsUpdate event log not found: {Channel} (normal on non-Windows 10/11 test environments)");
+                _logger.Warning($"WindowsUpdate event log not found: {_channel} (normal on non-Windows 10/11 test environments)");
             }
             catch (UnauthorizedAccessException ex)
             {
-                _logger.Warning($"WindowsUpdate watcher access denied for {Channel}: {ex.Message}");
+                _logger.Warning($"WindowsUpdate watcher access denied for {_channel}: {ex.Message}");
             }
             catch (Exception ex)
             {
-                _logger.Error($"Failed to start WindowsUpdate watcher for {Channel}", ex);
+                _logger.Error($"Failed to start WindowsUpdate watcher for {_channel}", ex);
                 // MON-D1: surface a dead watcher as one-shot telemetry, not just a local log line.
                 CollectorDegradationReporter.Report(_post, _sessionId, _tenantId,
-                    collectorName: "WindowsUpdateTracker", reason: $"watcher_arm_failed:{Channel}", ex: ex);
+                    collectorName: "WindowsUpdateTracker", reason: $"watcher_arm_failed:{_channel}", ex: ex);
             }
         }
 
+        /// <summary>Targeted-EventID XPath filter without a provider clause. Exposed for tests.</summary>
+        internal static string BuildXPath(HashSet<int> targetedEventIds) =>
+            BuildXPath(targetedEventIds, providerName: null);
+
         /// <summary>
-        /// Builds the targeted-EventID XPath filter. Exposed as internal for tests.
+        /// Targeted-EventID XPath filter, optionally restricted to <paramref name="providerName"/>
+        /// (mandatory on the shared System log) and to the last <paramref name="lookbackMs"/>.
         /// </summary>
-        internal static string BuildXPath(HashSet<int> targetedEventIds)
+        internal static string BuildXPath(HashSet<int> targetedEventIds, string providerName, long? lookbackMs = null)
         {
-            var idClauses = string.Join(" or ",
-                targetedEventIds.OrderBy(id => id).Select(id => $"EventID={id}"));
-            return $"*[System[({idClauses})]]";
+            var clauses = new List<string>(3);
+            if (!string.IsNullOrEmpty(providerName))
+                clauses.Add($"Provider[@Name='{providerName}']");
+            clauses.Add("(" + string.Join(" or ", targetedEventIds.OrderBy(id => id).Select(id => $"EventID={id}")) + ")");
+            if (lookbackMs.HasValue)
+                clauses.Add($"TimeCreated[timediff(@SystemTime) <= {lookbackMs.Value}]");
+            return $"*[System[{string.Join(" and ", clauses)}]]";
         }
 
         // -----------------------------------------------------------------------
@@ -230,7 +281,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             var recordId = record.RecordId ?? -1;
 
             // Cheap dedup gate BEFORE the expensive XML/FormatDescription work.
-            if (IsAlreadyProcessed(recordId))
+            if (_watermark.IsAlreadyProcessed(recordId))
                 return;
 
             string xml = null;
@@ -242,6 +293,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             eventData.TryGetValue("updateGuid", out var updateGuid);
             eventData.TryGetValue("updateRevisionNumber", out var updateRevision);
             eventData.TryGetValue("errorCode", out var errorCode);
+            eventData.TryGetValue("serviceGuid", out var serviceGuid);
+            eventData.TryGetValue("updateCount", out var updateCount);
 
             string description = null;
             try { description = record.FormatDescription(); }
@@ -257,7 +310,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 updateRevisionNumber: updateRevision,
                 errorCode: errorCode,
                 formattedDescription: description,
-                isBackfill: isBackfill);
+                isBackfill: isBackfill,
+                serviceGuid: serviceGuid,
+                updateCount: updateCount);
         }
 
         /// <summary>
@@ -275,66 +330,68 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             string updateRevisionNumber,
             string errorCode,
             string formattedDescription,
-            bool isBackfill)
+            bool isBackfill,
+            string serviceGuid = null,
+            string updateCount = null)
         {
-            if (!MarkProcessed(recordId))
+            if (!_watermark.TryClaim(recordId))
                 return; // already emitted (cross-restart or duplicate delivery)
 
-            System.Threading.Interlocked.Increment(ref _emittedThisRun);
+            Interlocked.Increment(ref _emittedThisRun);
 
-            string eventType;
-            EventSeverity severity;
-            bool immediateUpload;
-            ClassifyEventId(eventId, out eventType, out severity, out immediateUpload);
+            var shape = ShapeFor(eventId);
+            var title = string.IsNullOrEmpty(updateTitle) ? "(unknown update)" : updateTitle;
+
+            // Scan-level events name no update: deduplicate instead of classifying. Every other
+            // event is classified; only Windows/.NET updates are listed, the rest is counted —
+            // so windows_update_succeeded/failed always mean an OS update (ANALYZE-DEV-004/005).
+            string updateClass = null;
+            if (eventId == EventId_ScanFound)
+            {
+                if (!ClaimScanFoundEmission(updateCount)) { _tally?.Increment("scan_found_repeat"); return; }
+            }
+            else if (eventId == EventId_ScanFailed)
+            {
+                if (!ClaimScanFailedEmission(errorCode)) { _tally?.Increment("scan_failed_repeat"); return; }
+            }
+            else
+            {
+                updateClass = WindowsUpdateClassifier.Classify(updateTitle, serviceGuid);
+                if (updateClass != WindowsUpdateClassifier.Os)
+                {
+                    _tally?.Increment($"{updateClass}_{eventId}");
+                    return;
+                }
+            }
 
             var data = new Dictionary<string, object>
             {
                 { "wuEventId", eventId },
+                { "wuChannel", _isSystemChannel ? "system" : "operational" },
+                { "wuPhase", shape.Phase },
                 { "backfilled", isBackfill },
             };
+            if (updateClass != null) data["updateClass"] = updateClass;
             if (recordId >= 0) data["recordId"] = recordId;
             if (level.HasValue) data["level"] = level.Value;
             if (!string.IsNullOrEmpty(updateTitle)) data["updateTitle"] = updateTitle;
             if (!string.IsNullOrEmpty(updateGuid)) data["updateGuid"] = updateGuid;
             if (!string.IsNullOrEmpty(updateRevisionNumber)) data["updateRevisionNumber"] = updateRevisionNumber;
+            if (!string.IsNullOrEmpty(updateCount)) data["updateCount"] = updateCount;
             if (timeCreatedUtc.HasValue) data["timeCreated"] = timeCreatedUtc.Value.ToString("o");
 
             // Decode the HRESULT for failure events (and any event that carries a non-empty errorCode).
-            string hresultHex;
-            if (TryNormalizeHResult(errorCode, out var hresultValue, out hresultHex))
+            if (TryNormalizeHResult(errorCode, out var hresultValue, out var hresultHex))
             {
                 data["hresult"] = hresultHex;
                 data["hresultSymbol"] = ResolveHResultSymbol(hresultValue);
             }
 
-            var title = string.IsNullOrEmpty(updateTitle) ? "(unknown update)" : updateTitle;
-            string message;
-            switch (eventId)
-            {
-                case EventId_InstallSuccess:
-                    message = $"Windows Update installed during enrollment: {title}";
-                    break;
-                case EventId_InstallFailure:
-                    message = data.TryGetValue("hresultSymbol", out var sym)
-                        ? $"Windows Update FAILED during enrollment: {title} ({data["hresult"]} {sym})"
-                        : $"Windows Update FAILED during enrollment: {title}";
-                    break;
-                case EventId_DownloadStarted:
-                    message = $"Windows Update download started during enrollment: {title}";
-                    break;
-                case EventId_InstallStarted:
-                    message = $"Windows Update install started during enrollment: {title}";
-                    break;
-                default:
-                    message = $"Windows Update activity (EventID {eventId}) during enrollment: {title}";
-                    break;
-            }
             if (!string.IsNullOrEmpty(formattedDescription))
             {
-                var truncated = formattedDescription.Length > 1000
+                data["description"] = formattedDescription.Length > 1000
                     ? formattedDescription.Substring(0, 1000) + "…"
                     : formattedDescription;
-                data["description"] = truncated;
             }
 
             _post.Emit(new EnrollmentEvent
@@ -343,46 +400,107 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 TenantId = _tenantId,
                 // Use the WU event's own time, not the default UtcNow the ctor stamps: backfilled
                 // pre-agent OOBE updates must land on the timeline at when the update actually
-                // installed, not at agent start. InformationalEventPost forwards this as occurredAtUtc,
+                // happened, not at agent start. InformationalEventPost forwards this as occurredAtUtc,
                 // which drives the timeline entry's timestamp (EventTimelineEmitter).
                 Timestamp = timeCreatedUtc ?? DateTime.UtcNow,
-                EventType = eventType,
-                Severity = severity,
-                Source = "WindowsUpdateWatcher",
+                EventType = shape.EventType,
+                Severity = shape.Severity,
+                Source = Constants.EventSources.WindowsUpdateWatcher,
                 Phase = EnrollmentPhase.Unknown,
-                Message = message,
+                Message = BuildMessage(eventId, title, updateCount, data),
                 Data = data,
-                ImmediateUpload = immediateUpload,
+                ImmediateUpload = shape.Immediate,
             });
+
+            if (updateClass == WindowsUpdateClassifier.Os && shape.OsStep != null && _onOsUpdateActivity != null)
+            {
+                try { _onOsUpdateActivity(shape.OsStep, updateTitle, timeCreatedUtc ?? DateTime.UtcNow); }
+                catch (Exception ex) { _logger.Warning($"WindowsUpdate: OS update activity callback failed: {ex.Message}"); }
+            }
+
+            // Last: everything this record produced has been handed to the ingress first.
+            _watermark.MarkEmitted(recordId);
         }
 
-        private static void ClassifyEventId(int eventId, out string eventType, out EventSeverity severity, out bool immediateUpload)
+        private struct EventShape
+        {
+            public string EventType;
+            public EventSeverity Severity;
+            public bool Immediate;
+            public string Phase;
+            /// <summary>Step reported to the decision engine for OS updates; null = not a step.</summary>
+            public string OsStep;
+        }
+
+        private static EventShape ShapeFor(int eventId)
         {
             switch (eventId)
             {
-                case EventId_InstallFailure:
-                    eventType = Constants.EventTypes.WindowsUpdateFailed;
-                    severity = EventSeverity.Error;
-                    immediateUpload = true; // a mid-OOBE update failure is high-signal — surface it fast
-                    break;
                 case EventId_InstallSuccess:
-                    eventType = Constants.EventTypes.WindowsUpdateSucceeded;
-                    severity = EventSeverity.Info;
-                    immediateUpload = false;
-                    break;
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateSucceeded, Severity = EventSeverity.Info, Phase = "installed", OsStep = OsUpdateSteps.Installed };
+                case EventId_InstallFailure:
+                    // A mid-OOBE install failure is high-signal — surface it fast.
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateFailed, Severity = EventSeverity.Error, Immediate = true, Phase = "install", OsStep = OsUpdateSteps.Failed };
                 case EventId_InstallStarted:
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateStarted, Severity = EventSeverity.Info, Phase = "install", OsStep = OsUpdateSteps.InstallStarted };
                 case EventId_DownloadStarted:
-                    eventType = Constants.EventTypes.WindowsUpdateStarted;
-                    severity = EventSeverity.Debug; // timeline context only
-                    immediateUpload = false;
-                    break;
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateStarted, Severity = EventSeverity.Info, Phase = "download", OsStep = OsUpdateSteps.DownloadStarted };
+                case EventId_Downloaded:
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateStarted, Severity = EventSeverity.Info, Phase = "downloaded", OsStep = OsUpdateSteps.Downloaded };
+                case EventId_DownloadFailed:
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateFailed, Severity = EventSeverity.Warning, Phase = "download", OsStep = OsUpdateSteps.Failed };
+                case EventId_ScanFailed:
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateFailed, Severity = EventSeverity.Warning, Phase = "scan" };
+                case EventId_ScanFound:
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateStarted, Severity = EventSeverity.Debug, Phase = "scan" };
                 default:
-                    // A newly-enabled (still-being-validated) EventID: keep it visible (Info, not Debug)
-                    // so it can be assessed on real traces.
-                    eventType = Constants.EventTypes.WindowsUpdateStarted;
-                    severity = EventSeverity.Info;
-                    immediateUpload = false;
-                    break;
+                    // An EventID enabled via config whose meaning has not been mapped: keep it
+                    // visible (Info, not Debug) so it can be assessed on real traces.
+                    return new EventShape { EventType = Constants.EventTypes.WindowsUpdateStarted, Severity = EventSeverity.Info, Phase = "activity" };
+            }
+        }
+
+        private static string BuildMessage(int eventId, string title, string updateCount, Dictionary<string, object> data)
+        {
+            var hresultSuffix = data.TryGetValue("hresultSymbol", out var sym)
+                ? $" ({data["hresult"]} {sym})"
+                : string.Empty;
+
+            switch (eventId)
+            {
+                case EventId_InstallSuccess:  return $"Windows Update installed during enrollment: {title}";
+                case EventId_InstallFailure:  return $"Windows Update FAILED during enrollment: {title}{hresultSuffix}";
+                case EventId_InstallStarted:  return $"Windows Update install started during enrollment: {title}";
+                case EventId_DownloadStarted: return $"Windows Update download started during enrollment: {title}";
+                case EventId_Downloaded:      return $"Windows Update downloaded during enrollment: {title}";
+                case EventId_DownloadFailed:  return $"Windows Update download FAILED during enrollment: {title}{hresultSuffix}";
+                case EventId_ScanFailed:      return $"Windows Update scan failed during enrollment{hresultSuffix}";
+                case EventId_ScanFound:
+                    return string.IsNullOrEmpty(updateCount)
+                        ? "Windows Update scan completed during enrollment"
+                        : $"Windows Update scan found {updateCount} update(s) during enrollment";
+                default:                      return $"Windows Update activity (EventID {eventId}) during enrollment: {title}";
+            }
+        }
+
+        private bool ClaimScanFoundEmission(string updateCount)
+        {
+            lock (_throttleLock)
+            {
+                if (_scanFoundEmitted >= MaxScanFoundEmissions) return false;
+                if (string.Equals(_lastScanFoundCount, updateCount ?? string.Empty, StringComparison.Ordinal)) return false;
+                _lastScanFoundCount = updateCount ?? string.Empty;
+                _scanFoundEmitted++;
+                return true;
+            }
+        }
+
+        private bool ClaimScanFailedEmission(string errorCode)
+        {
+            lock (_throttleLock)
+            {
+                if (_scanFailureCodesReported.Count >= MaxScanFailedEmissions) return false;
+                return _scanFailureCodesReported.Add(errorCode ?? string.Empty);
             }
         }
 
@@ -496,14 +614,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             try
             {
                 var lookbackMs = (long)_backfillLookbackMinutes * 60 * 1000;
-                var idClauses = string.Join(" or ",
-                    _targetedEventIds.OrderBy(id => id).Select(id => $"EventID={id}"));
-                var xpath = $"*[System[({idClauses}) and TimeCreated[timediff(@SystemTime) <= {lookbackMs}]]]";
+                var xpath = BuildXPath(_targetedEventIds, ProviderFilter, lookbackMs);
 
-                _logger.Info($"WindowsUpdate backfill: scanning {Channel} " +
-                    $"(lookback={_backfillLookbackMinutes}min, targetedIds={_targetedEventIds.Count}, restartWatermark={_restartWatermark})");
+                _logger.Info($"WindowsUpdate backfill: scanning {_channel} " +
+                    $"(lookback={_backfillLookbackMinutes}min, targetedIds={_targetedEventIds.Count}, restartWatermark={_watermark.RestartWatermark})");
 
-                var query = new EventLogQuery(Channel, PathType.LogName, xpath);
+                var query = new EventLogQuery(_channel, PathType.LogName, xpath);
 
                 int processed = 0;
                 using (var reader = new EventLogReader(query))
@@ -520,21 +636,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 }
 
                 if (processed == 0)
-                    _logger.Debug($"WindowsUpdate backfill: no targeted events in last {_backfillLookbackMinutes} minutes");
+                    _logger.Debug($"WindowsUpdate backfill: no targeted events in last {_backfillLookbackMinutes} minutes ({_channel})");
                 else
-                    _logger.Info($"WindowsUpdate backfill: scanned {processed} event(s)");
+                    _logger.Info($"WindowsUpdate backfill: scanned {processed} event(s) ({_channel})");
             }
             catch (EventLogNotFoundException)
             {
-                _logger.Warning($"WindowsUpdate event log not found during backfill: {Channel} (normal on non-Windows 10/11 test environments)");
+                _logger.Warning($"WindowsUpdate event log not found during backfill: {_channel} (normal on non-Windows 10/11 test environments)");
             }
             catch (UnauthorizedAccessException ex)
             {
-                _logger.Warning($"WindowsUpdate backfill access denied: {ex.Message}");
+                _logger.Warning($"WindowsUpdate backfill access denied ({_channel}): {ex.Message}");
             }
             catch (Exception ex)
             {
-                _logger.Warning($"WindowsUpdate backfill failed: {ex.Message}");
+                _logger.Warning($"WindowsUpdate backfill failed ({_channel}): {ex.Message}");
             }
         }
 
@@ -544,17 +660,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
         /// <summary>
         /// Self-evidencing blind spot diagnosis. Session 7443317c: an OOBE quality update
-        /// provably installed (OS build changed across the mid-enrollment reboot) yet neither
-        /// the live watcher nor two 60-min backfills captured a single targeted event — the
-        /// update logged via a channel/EventID set the watcher is blind to. With diagnostics
-        /// upload tenant-disabled there is no client-log path to find out which one; so when
-        /// the blind spot provably occurred (build changed AND zero targeted events emitted
-        /// this run), emit a one-shot unfiltered EventID histogram of both update channels
-        /// over the lookback window. The histogram arrives via normal event upload and tells
-        /// us which IDs to add to <c>WindowsUpdateTargetedEventIds</c> via remote config —
-        /// no agent redeploy, no diagnostics access needed.
+        /// provably installed (OS build changed across the mid-enrollment reboot) yet the watcher
+        /// captured nothing — it read the install IDs from the Operational channel, while the
+        /// manifest writes them to the System log (D-310). When the blind spot occurs again
+        /// (build changed AND zero targeted events on every channel this run), emit a one-shot
+        /// unfiltered EventID histogram of the Operational and UpdateOrchestrator channels.
         /// </summary>
-        internal void EmitChannelCensusIfBlind()
+        /// <param name="otherChannelsEmitted">Targeted events the host's other update watchers processed this run.</param>
+        /// <param name="otherTargetedEventIds">EventIDs the host's other update watchers target, listed with this instance's own.</param>
+        internal void EmitChannelCensusIfBlind(int otherChannelsEmitted = 0, IEnumerable<int> otherTargetedEventIds = null)
         {
             if (!_channelCensusEnabled) return;
 
@@ -562,7 +676,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             {
                 if (_osBuildChangedProvider == null || !_osBuildChangedProvider())
                     return;
-                if (System.Threading.Volatile.Read(ref _emittedThisRun) > 0)
+                if (EmittedThisRun + otherChannelsEmitted > 0)
                     return;
 
                 var lookback = _backfillLookbackMinutes > 0 ? _backfillLookbackMinutes : 60;
@@ -581,8 +695,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                     { "wuClientCensus", wuClientHistogram },
                     { "updateOrchestratorCensus", orchestratorHistogram },
                     { "lookbackMinutes", lookback },
-                    { "restartWatermark", _restartWatermark },
-                    { "targetedEventIds", string.Join(",", _targetedEventIds.OrderBy(id => id)) },
+                    { "restartWatermark", _watermark.RestartWatermark },
+                    { "targetedEventIds", string.Join(",", _targetedEventIds.Concat(otherTargetedEventIds ?? Enumerable.Empty<int>()).Distinct().OrderBy(id => id)) },
                 };
                 if (wuClient.Truncated || orchestrator.Truncated)
                     data["censusTruncated"] = true;
@@ -593,7 +707,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                     TenantId = _tenantId,
                     EventType = Constants.EventTypes.WindowsUpdateChannelCensus,
                     Severity = EventSeverity.Debug,
-                    Source = "WindowsUpdateWatcher",
+                    Source = Constants.EventSources.WindowsUpdateWatcher,
                     Phase = EnrollmentPhase.Unknown,
                     Message = "Windows Update channel census: OS build changed across restart but no targeted WU events were captured — EventID histogram attached",
                     Data = data,
@@ -666,102 +780,5 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// <summary>Compact "id=count" form ordered by EventID, e.g. "19=2,25=1,43=2".</summary>
         internal static string FormatHistogram(Dictionary<int, int> histogram) =>
             string.Join(",", histogram.OrderBy(kv => kv.Key).Select(kv => $"{kv.Key}={kv.Value}"));
-
-        // -----------------------------------------------------------------------
-        // Watermark dedup (cross-restart)
-        // -----------------------------------------------------------------------
-
-        private bool IsAlreadyProcessed(long recordId)
-        {
-            if (recordId < 0) return false; // no RecordId → cannot dedup, let it through
-            lock (_watermarkLock)
-            {
-                return recordId <= _restartWatermark || _seenThisRun.Contains(recordId);
-            }
-        }
-
-        /// <summary>
-        /// Atomically claims <paramref name="recordId"/>. Returns true if this is the first time we
-        /// see it (caller should emit), false if it was already processed — either in a PRIOR run
-        /// (at/below the restart watermark) or already this run (in the seen-set). Only advances +
-        /// persists the max on a genuinely-new, higher RecordId. Records without a RecordId (-1) are
-        /// always emitted, never tracked or persisted.
-        /// </summary>
-        private bool MarkProcessed(long recordId)
-        {
-            if (recordId < 0) return true;
-
-            long toPersist = -1;
-            lock (_watermarkLock)
-            {
-                // Prior run, or already emitted this run. Note: a lower RecordId that was never
-                // emitted this run (e.g. a backfill record read after a higher live record) is NOT
-                // in _seenThisRun and is above the restart watermark, so it is correctly emitted.
-                if (recordId <= _restartWatermark || !_seenThisRun.Add(recordId))
-                    return false;
-
-                if (recordId > _maxEmittedRecordId)
-                {
-                    _maxEmittedRecordId = recordId;
-                    toPersist = _maxEmittedRecordId;
-                }
-            }
-            if (toPersist >= 0) PersistWatermark(toPersist);
-            return true;
-        }
-
-        internal void LoadWatermark()
-        {
-            if (string.IsNullOrEmpty(_stateDirectory)) return;
-
-            var filePath = Path.Combine(_stateDirectory, WatermarkStateFileName);
-            if (!File.Exists(filePath)) return;
-
-            try
-            {
-                var json = File.ReadAllText(filePath);
-                var state = JsonConvert.DeserializeObject<WatermarkState>(json);
-                if (state != null)
-                {
-                    lock (_watermarkLock)
-                    {
-                        _restartWatermark = state.LastRecordId;
-                        _maxEmittedRecordId = state.LastRecordId;
-                    }
-                    _logger.Info($"WindowsUpdate watermark loaded: lastRecordId={state.LastRecordId} (persisted {state.PersistedUtc:O})");
-                }
-            }
-            catch (Exception ex)
-            {
-                _logger.Warning($"Failed to load WindowsUpdate watermark: {ex.Message}");
-            }
-        }
-
-        private void PersistWatermark(long recordId)
-        {
-            if (string.IsNullOrEmpty(_stateDirectory)) return;
-
-            try
-            {
-                Directory.CreateDirectory(_stateDirectory);
-                var filePath = Path.Combine(_stateDirectory, WatermarkStateFileName);
-                var state = new WatermarkState { LastRecordId = recordId, PersistedUtc = DateTime.UtcNow };
-                var json = JsonConvert.SerializeObject(state, Formatting.Indented);
-                var tempPath = filePath + ".tmp";
-                File.WriteAllText(tempPath, json);
-                File.Copy(tempPath, filePath, overwrite: true);
-                try { File.Delete(tempPath); } catch { }
-            }
-            catch (Exception ex)
-            {
-                _logger.Warning($"Failed to persist WindowsUpdate watermark: {ex.Message}");
-            }
-        }
-
-        internal sealed class WatermarkState
-        {
-            public long LastRecordId { get; set; }
-            public DateTime PersistedUtc { get; set; }
-        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Runtime/DiagnosticsPackageService.cs

@@ -472,7 +472,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
 
                         // Expand BEFORE the guard: the guard must judge the path that is read,
                         // and an unresolved token is not a path it can judge.
-                        var expandedPath = UserProfileResolver.ExpandCustomTokens(entry.Path);
+                        var expandedPath = UserProfileResolver.ExpandCustomTokens(entry.Path, userProfilePath);
                         if (expandedPath == null)
                         {
                             _logger.Warning($"Diagnostics path skipped (no user session for token): {entry.Path}");

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Runtime/UserProfileResolver.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Diagnostics;
 using System.IO;
+using System.Threading;
 using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment;
 using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
 using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
@@ -14,7 +15,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
     /// The agent runs as SYSTEM, so standard environment variables like %USERPROFILE% or
     /// %LOCALAPPDATA% resolve to the SYSTEM profile — not the logged-on user. This class
     /// detects the real user via explorer.exe ownership (WTS session query, WMI fallback —
-    /// see <see cref="Interop.ProcessOwnerLookup"/>) and caches the result for the agent's lifetime.
+    /// see <see cref="Interop.ProcessOwnerLookup"/>) and caches the first user it finds for the
+    /// agent's lifetime. "No user yet" is not cached: the agent usually starts before anyone has
+    /// signed in, so detection is retried — at most every <see cref="RetryInterval"/>.
     ///
     /// Usage in paths: %LOGGED_ON_USER_PROFILE%\AppData\Local\RealmJoin\Logs\*.log
     /// </summary>
@@ -23,9 +26,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
         // Spelled once, in Shared: the built-in diagnostics catalog uses the same token.
         public const string Token = Shared.Models.DiagnosticsBuiltInSections.UserProfileToken;
 
+        /// <summary>Minimum time between two detections while no user has been found.</summary>
+        internal static readonly TimeSpan RetryInterval = TimeSpan.FromSeconds(30);
+
         private static readonly object Lock = new object();
-        private static bool _resolved;
-        private static string _userProfilePath; // e.g. C:\Users\JohnDoe — null if no user detected
+        private static string _userProfilePath; // e.g. C:\Users\JohnDoe — null until a user is detected
+        private static DateTime _lastFailedDetectionUtc = DateTime.MinValue;
+
+        // Seams for tests; production uses the real detection and clock.
+        private static Func<string> _detector = DetectLoggedOnUserProfile;
+        private static Func<DateTime> _utcNow = () => DateTime.UtcNow;
 
         /// <summary>
         /// Returns the logged-on user's profile path (e.g. C:\Users\JohnDoe) or null
@@ -34,17 +44,28 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
         /// </summary>
         public static string GetLoggedOnUserProfilePath()
         {
-            if (_resolved)
-                return _userProfilePath;
+            var cached = Volatile.Read(ref _userProfilePath);
+            if (cached != null)
+                return cached;
 
             lock (Lock)
             {
-                if (_resolved)
+                if (_userProfilePath != null)
                     return _userProfilePath;
 
-                _userProfilePath = DetectLoggedOnUserProfile();
-                _resolved = true;
-                return _userProfilePath;
+                // A clock that stepped backwards (common during OOBE) never delays the retry.
+                var now = _utcNow();
+                var sinceLastFailure = now - _lastFailedDetectionUtc;
+                if (_lastFailedDetectionUtc != DateTime.MinValue
+                    && sinceLastFailure >= TimeSpan.Zero && sinceLastFailure < RetryInterval)
+                    return null;
+
+                var detected = _detector();
+                if (detected != null)
+                    Volatile.Write(ref _userProfilePath, detected);
+                else
+                    _lastFailedDetectionUtc = now;
+                return detected;
             }
         }
 
@@ -53,18 +74,26 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
         /// Environment.ExpandEnvironmentVariables for standard tokens.
         /// Returns null if the path contains the token but no user is logged on.
         /// </summary>
-        public static string ExpandCustomTokens(string rawPath)
+        public static string ExpandCustomTokens(string rawPath) =>
+            ExpandCustomTokens(rawPath, ContainsUserProfileToken(rawPath) ? GetLoggedOnUserProfilePath() : null);
+
+        /// <summary>
+        /// Same, with the profile path the caller already resolved for its guard. Callers that
+        /// guard the expanded path must use this overload: while detection is still retrying, a
+        /// second lookup can find the user the first one missed, and the guard would then judge a
+        /// C:\Users path without the profile that admits it.
+        /// </summary>
+        public static string ExpandCustomTokens(string rawPath, string userProfilePath)
         {
             if (string.IsNullOrEmpty(rawPath))
                 return rawPath;
 
             if (rawPath.IndexOf(Token, StringComparison.OrdinalIgnoreCase) >= 0)
             {
-                var profilePath = GetLoggedOnUserProfilePath();
-                if (profilePath == null)
+                if (userProfilePath == null)
                     return null; // No user detected — caller should skip this path
 
-                rawPath = ReplaceCaseInsensitive(rawPath, Token, profilePath);
+                rawPath = ReplaceCaseInsensitive(rawPath, Token, userProfilePath);
             }
 
             return Environment.ExpandEnvironmentVariables(rawPath);
@@ -80,26 +109,37 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
         }
 
         /// <summary>
-        /// Resets the cached state. Only used for testing.
+        /// Resets the cached state and the seams. Only used for testing.
         /// </summary>
         internal static void Reset()
         {
             lock (Lock)
             {
-                _resolved = false;
                 _userProfilePath = null;
+                _lastFailedDetectionUtc = DateTime.MinValue;
+                _detector = DetectLoggedOnUserProfile;
+                _utcNow = () => DateTime.UtcNow;
             }
         }
 
         /// <summary>
-        /// Allows tests to inject a specific profile path without WMI.
+        /// Allows tests to inject a specific profile path without WMI. Null pins "no user signed in"
+        /// — detection keeps answering null instead of finding the developer's own session.
         /// </summary>
         internal static void SetForTesting(string profilePath)
+        {
+            SetDetectorForTesting(() => profilePath, () => DateTime.UtcNow);
+        }
+
+        /// <summary>Replaces detection and clock, clearing what was cached. Only used for testing.</summary>
+        internal static void SetDetectorForTesting(Func<string> detector, Func<DateTime> utcNow)
         {
             lock (Lock)
             {
-                _userProfilePath = profilePath;
-                _resolved = true;
+                _userProfilePath = null;
+                _lastFailedDetectionUtc = DateTime.MinValue;
+                _detector = detector ?? throw new ArgumentNullException(nameof(detector));
+                _utcNow = utcNow ?? throw new ArgumentNullException(nameof(utcNow));
             }
         }
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/Collectors/FileCollector.cs

@@ -23,7 +23,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             // Expand custom tokens (%LOGGED_ON_USER_PROFILE%) and standard environment variables
             var userProfilePath = UserProfileResolver.ContainsUserProfileToken(filePath)
                 ? UserProfileResolver.GetLoggedOnUserProfilePath() : null;
-            filePath = UserProfileResolver.ExpandCustomTokens(filePath);
+            filePath = UserProfileResolver.ExpandCustomTokens(filePath, userProfilePath);
             if (filePath == null)
                 return data; // Token present but no user logged on — skip silently
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/Collectors/JsonCollector.cs

@@ -24,7 +24,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             // Expand custom tokens (%LOGGED_ON_USER_PROFILE%) and standard environment variables
             var userProfilePath = UserProfileResolver.ContainsUserProfileToken(filePath)
                 ? UserProfileResolver.GetLoggedOnUserProfilePath() : null;
-            filePath = UserProfileResolver.ExpandCustomTokens(filePath);
+            filePath = UserProfileResolver.ExpandCustomTokens(filePath, userProfilePath);
             if (filePath == null)
                 return data; // Token present but no user logged on — skip silently
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/Collectors/LogLineReader.cs

@@ -0,0 +1,313 @@
+using System;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
+{
+    /// <summary>
+    /// Text encoding of a log file as the logparser reads it. Chosen from the byte order mark at
+    /// the start of the file in <see cref="StreamReader"/>'s detection order; without one the file
+    /// is UTF-8, which is also how ANSI logs were always read (invalid bytes decode to U+FFFD).
+    /// </summary>
+    internal sealed class LogTextEncoding
+    {
+        public static readonly LogTextEncoding Utf8 = new LogTextEncoding("utf-8", new UTF8Encoding(false), 1, 0);
+        public static readonly LogTextEncoding Utf8WithBom = new LogTextEncoding("utf-8 with bom", new UTF8Encoding(false), 1, 3);
+        public static readonly LogTextEncoding Utf16LittleEndian = new LogTextEncoding("utf-16le", new UnicodeEncoding(false, false), 2, 2);
+        public static readonly LogTextEncoding Utf16BigEndian = new LogTextEncoding("utf-16be", new UnicodeEncoding(true, false), 2, 2);
+        public static readonly LogTextEncoding Utf32LittleEndian = new LogTextEncoding("utf-32le", new UTF32Encoding(false, false), 4, 4);
+        public static readonly LogTextEncoding Utf32BigEndian = new LogTextEncoding("utf-32be", new UTF32Encoding(true, false), 4, 4);
+
+        private LogTextEncoding(string name, Encoding encoding, int unitSize, int byteOrderMarkLength)
+        {
+            Name = name;
+            Encoding = encoding;
+            UnitSize = unitSize;
+            ByteOrderMarkLength = byteOrderMarkLength;
+            LineFeed = encoding.GetBytes("\n");
+            CarriageReturn = encoding.GetBytes("\r");
+        }
+
+        public string Name { get; }
+        public Encoding Encoding { get; }
+
+        /// <summary>Bytes per code unit; every line boundary lies on a unit boundary.</summary>
+        public int UnitSize { get; }
+
+        /// <summary>Length of the byte order mark at offset 0 — skipped, never part of a line.</summary>
+        public int ByteOrderMarkLength { get; }
+
+        public byte[] LineFeed { get; }
+        public byte[] CarriageReturn { get; }
+
+        public static LogTextEncoding Detect(byte[] head)
+        {
+            if (StartsWith(head, 0xEF, 0xBB, 0xBF)) return Utf8WithBom;
+            if (StartsWith(head, 0xFF, 0xFE, 0x00, 0x00)) return Utf32LittleEndian;
+            if (StartsWith(head, 0xFF, 0xFE)) return Utf16LittleEndian;
+            if (StartsWith(head, 0xFE, 0xFF)) return Utf16BigEndian;
+            if (StartsWith(head, 0x00, 0x00, 0xFE, 0xFF)) return Utf32BigEndian;
+            return Utf8;
+        }
+
+        /// <summary>The last code-unit boundary at or before <paramref name="position"/>.</summary>
+        public long AlignDown(long position)
+        {
+            if (position <= ByteOrderMarkLength) return position < ByteOrderMarkLength ? 0 : position;
+            return position - (position - ByteOrderMarkLength) % UnitSize;
+        }
+
+        private static bool StartsWith(byte[] bytes, params byte[] prefix)
+        {
+            if (bytes.Length < prefix.Length) return false;
+            for (var i = 0; i < prefix.Length; i++)
+                if (bytes[i] != prefix[i]) return false;
+            return true;
+        }
+    }
+
+    /// <summary>
+    /// The first bytes of a log file: they carry its byte order mark and identify the file, so a
+    /// file replaced under the same name is recognised even when it is already longer than the
+    /// position read so far.
+    /// </summary>
+    internal sealed class LogFileHead
+    {
+        internal const int MaxBytes = 4096;
+
+        private readonly byte[] _bytes;
+
+        private LogFileHead(byte[] bytes)
+        {
+            _bytes = bytes;
+        }
+
+        /// <summary>Up to <see cref="MaxBytes"/> from offset 0. Leaves the stream at an undefined position.</summary>
+        public static LogFileHead Read(Stream stream)
+        {
+            stream.Seek(0, SeekOrigin.Begin);
+            var buffer = new byte[(int)Math.Min(MaxBytes, stream.Length)];
+            var read = 0;
+            while (read < buffer.Length)
+            {
+                var n = stream.Read(buffer, read, buffer.Length - read);
+                if (n <= 0) break;
+                read += n;
+            }
+            if (read < buffer.Length) Array.Resize(ref buffer, read);
+            return new LogFileHead(buffer);
+        }
+
+        internal static LogFileHead FromBytes(byte[] bytes) => new LogFileHead(bytes);
+
+        public int Length => _bytes.Length;
+
+        public LogTextEncoding Encoding => LogTextEncoding.Detect(_bytes);
+
+        /// <summary>SHA-256 of the first <paramref name="length"/> bytes, Base64.</summary>
+        public string Hash(int length)
+        {
+            using (var sha = SHA256.Create())
+                return Convert.ToBase64String(sha.ComputeHash(_bytes, 0, length));
+        }
+    }
+
+    /// <summary>
+    /// Byte-exact line reader for the logparser collector. <see cref="Position"/> is the file
+    /// offset right behind the last line returned, so a caller that stops after any line can
+    /// resume exactly there — <see cref="StreamReader"/> only exposes its read-ahead boundary.
+    /// <para>
+    /// Line ends are those of <see cref="StreamReader.ReadLine"/>: "\r\n", "\n" and a lone "\r",
+    /// in code units of the file's <see cref="LogTextEncoding"/>. A "\n" directly after the start
+    /// position is skipped when the unit before it is "\r": the previous run ended on a "\r" whose
+    /// "\n" had not been written yet. A line at end of file without a line end is returned with
+    /// <see cref="LastLineTerminated"/> false; the caller decides whether the writer is still in
+    /// it. A line longer than the cap is consumed without being kept: <see cref="ReadLine"/>
+    /// returns an empty string and sets <see cref="LastLineTruncated"/>.
+    /// </para>
+    /// </summary>
+    internal sealed class LogLineReader
+    {
+        private const int ReadBufferSize = 64 * 1024;
+
+        private readonly Stream _stream;
+        private readonly LogTextEncoding _encoding;
+        private readonly int _unit;
+        private readonly int _maxLineBytes;
+        private readonly byte[] _buffer = new byte[ReadBufferSize];
+        private int _pos;
+        private int _len;
+        private long _bufferOffset;
+        private bool _eof;
+        private bool _skipLineFeedAfterCarriageReturn;
+
+        private byte[] _line = new byte[4096];
+        private int _lineLength;
+
+        /// <param name="stream">Seekable stream positioned at a code-unit boundary.</param>
+        public LogLineReader(Stream stream, LogTextEncoding encoding, int maxLineBytes)
+        {
+            if (stream == null) throw new ArgumentNullException(nameof(stream));
+            if (encoding == null) throw new ArgumentNullException(nameof(encoding));
+            if (maxLineBytes <= 0) throw new ArgumentOutOfRangeException(nameof(maxLineBytes));
+            _stream = stream;
+            _encoding = encoding;
+            _unit = encoding.UnitSize;
+            _maxLineBytes = maxLineBytes;
+            _bufferOffset = stream.Position;
+            _skipLineFeedAfterCarriageReturn = PrecededByCarriageReturn();
+        }
+
+        /// <summary>File offset of the next unread byte, exact.</summary>
+        public long Position => _bufferOffset + _pos;
+
+        /// <summary>File offset of the first byte of the line most recently returned.</summary>
+        public long LastLineStart { get; private set; }
+
+        /// <summary>False for a line that reached end of file without a line end.</summary>
+        public bool LastLineTerminated { get; private set; }
+
+        /// <summary>True when the last line was longer than the cap; it was consumed, not returned.</summary>
+        public bool LastLineTruncated { get; private set; }
+
+        /// <summary>The next line without its line end, or null at end of file.</summary>
+        public string ReadLine()
+        {
+            if (Position == 0 && _encoding.ByteOrderMarkLength > 0 && Ensure(_encoding.ByteOrderMarkLength))
+                _pos += _encoding.ByteOrderMarkLength;
+
+            if (_skipLineFeedAfterCarriageReturn)
+            {
+                _skipLineFeedAfterCarriageReturn = false;
+                if (Ensure(_unit) && UnitAt(_pos, _encoding.LineFeed))
+                    _pos += _unit;
+            }
+
+            LastLineStart = Position;
+            LastLineTerminated = false;
+            LastLineTruncated = false;
+            _lineLength = 0;
+
+            while (true)
+            {
+                if (!Ensure(_unit))
+                {
+                    // End of file. A partial code unit (a writer mid-character) belongs to the line.
+                    var rest = _len - _pos;
+                    if (rest > 0)
+                    {
+                        Append(_pos, rest);
+                        _pos = _len;
+                    }
+                    return Position > LastLineStart ? Decode() : null;
+                }
+
+                // Scan the whole code units in the buffer for the next line end and take the text
+                // before it in one copy.
+                var end = _pos + (_len - _pos) / _unit * _unit;
+                var scan = _pos;
+                while (scan < end && !IsLineEnd(scan))
+                    scan += _unit;
+                if (scan > _pos)
+                {
+                    Append(_pos, scan - _pos);
+                    _pos = scan;
+                }
+                if (scan == end)
+                    continue;   // no line end in the buffer yet — refill
+
+                var carriageReturn = !UnitAt(_pos, _encoding.LineFeed);
+                _pos += _unit;
+                if (carriageReturn && Ensure(_unit) && UnitAt(_pos, _encoding.LineFeed))
+                    _pos += _unit;
+                LastLineTerminated = true;
+                return Decode();
+            }
+        }
+
+        private bool IsLineEnd(int offset)
+        {
+            if (_unit == 1)
+            {
+                var b = _buffer[offset];
+                return b == (byte)'\n' || b == (byte)'\r';
+            }
+            return UnitAt(offset, _encoding.LineFeed) || UnitAt(offset, _encoding.CarriageReturn);
+        }
+
+        private bool PrecededByCarriageReturn()
+        {
+            var start = _bufferOffset;
+            if (start - _unit < _encoding.ByteOrderMarkLength) return false;
+            var previous = new byte[_unit];
+            _stream.Seek(start - _unit, SeekOrigin.Begin);
+            var read = 0;
+            while (read < _unit)
+            {
+                var n = _stream.Read(previous, read, _unit - read);
+                if (n <= 0) break;
+                read += n;
+            }
+            _stream.Seek(start, SeekOrigin.Begin);
+            if (read < _unit) return false;
+            for (var i = 0; i < _unit; i++)
+                if (previous[i] != _encoding.CarriageReturn[i]) return false;
+            return true;
+        }
+
+        /// <summary>At least <paramref name="count"/> unread bytes in the buffer, unless the file ends first.</summary>
+        private bool Ensure(int count)
+        {
+            while (_len - _pos < count)
+            {
+                if (_eof) return false;
+                var remaining = _len - _pos;
+                if (_pos > 0)
+                {
+                    Buffer.BlockCopy(_buffer, _pos, _buffer, 0, remaining);
+                    _bufferOffset += _pos;
+                    _pos = 0;
+                    _len = remaining;
+                }
+                var read = _stream.Read(_buffer, _len, _buffer.Length - _len);
+                if (read <= 0)
+                {
+                    _eof = true;
+                    return _len - _pos >= count;
+                }
+                _len += read;
+            }
+            return true;
+        }
+
+        private bool UnitAt(int offset, byte[] unit)
+        {
+            for (var i = 0; i < _unit; i++)
+                if (_buffer[offset + i] != unit[i]) return false;
+            return true;
+        }
+
+        private void Append(int offset, int count)
+        {
+            var room = _maxLineBytes - _lineLength;
+            if (count > room)
+            {
+                LastLineTruncated = true;
+                count = room;
+                if (count <= 0) return;
+            }
+            if (_lineLength + count > _line.Length)
+            {
+                var grown = new byte[Math.Max(_line.Length * 2, _lineLength + count)];
+                Buffer.BlockCopy(_line, 0, grown, 0, _lineLength);
+                _line = grown;
+            }
+            Buffer.BlockCopy(_buffer, offset, _line, _lineLength, count);
+            _lineLength += count;
+        }
+
+        private string Decode() =>
+            _lineLength == 0 || LastLineTruncated ? string.Empty : _encoding.Encoding.GetString(_line, 0, _lineLength);
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/Collectors/LogParserCollector.cs

@@ -18,6 +18,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
     {
         public string CollectorType => "logparser";
 
+        /// <summary>A wildcard target reads at most this many files per run, the newest first.</summary>
+        internal const int MaxFilesPerRun = 20;
+
+        /// <summary>Lines one run reads from one file unless the rule sets <c>maxLines</c>.</summary>
+        internal const int DefaultMaxLines = 1000;
+
+        /// <summary>The IME tracker's line bound: a longer physical line is skipped, never matched.</summary>
+        internal const int MaxLineBytes = 32 * 1024 * 1024;
+
         /// <summary>
         /// Executes the log parser rule. Returns null because logparser emits events directly
         /// via context.OnEventCollected rather than returning a single result dictionary.
@@ -34,7 +43,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             // Expand custom tokens (%LOGGED_ON_USER_PROFILE%) and standard environment variables
             var userProfilePath = UserProfileResolver.ContainsUserProfileToken(filePath)
                 ? UserProfileResolver.GetLoggedOnUserProfilePath() : null;
-            filePath = UserProfileResolver.ExpandCustomTokens(filePath);
+            filePath = UserProfileResolver.ExpandCustomTokens(filePath, userProfilePath);
             if (filePath == null)
             {
                 context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
@@ -84,10 +93,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             if (rule.Parameters.TryGetValue("trackPosition", out trackPositionStr))
                 bool.TryParse(trackPositionStr, out trackPosition);
 
+            // A value that is no positive number keeps the default: a run capped at 0 lines would
+            // never advance its position, and the rule would read nothing for the whole session.
             string maxLinesStr;
-            int maxLines = 1000;
+            int maxLines = DefaultMaxLines;
             if (rule.Parameters.TryGetValue("maxLines", out maxLinesStr))
-                int.TryParse(maxLinesStr, out maxLines);
+            {
+                int parsedMaxLines;
+                if (int.TryParse(maxLinesStr, out parsedMaxLines) && parsedMaxLines > 0)
+                    maxLines = parsedMaxLines;
+                else
+                    context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                        $"maxLines '{maxLinesStr}' is not a positive number — using {DefaultMaxLines}");
+            }
 
             // Determine format: "cmtrace" (default) or "text" for plain text logs
             string formatStr;
@@ -144,7 +162,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
         /// as the event data). Stops after <see cref="MaxTracedMatchesPerFile"/> matches.
         /// </summary>
         private static void TraceMatch(GatherRuleContext context, GatherRule rule, string fileName,
-            int lineNumber, Match match, Regex pattern, int matchNumber)
+            long lineNumber, Match match, Regex pattern, int matchNumber)
         {
             if (matchNumber > MaxTracedMatchesPerFile)
             {
@@ -195,14 +213,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
 
             try
             {
-                // Return matched files sorted by last write time (newest first), capped at 20
+                // Return matched files sorted by last write time (newest first), capped at MaxFilesPerRun
                 var allMatches = Directory.GetFiles(directory, fileNamePart);
-                if (allMatches.Length > 20)
+                if (allMatches.Length > MaxFilesPerRun)
                     context.DebugLog(ruleId, GatherRuleDebugLog.StageLogParser,
-                        $"wildcard matched {allMatches.Length} files — capped to the 20 newest");
+                        $"wildcard matched {allMatches.Length} files — capped to the {MaxFilesPerRun} newest");
                 return allMatches
                     .OrderByDescending(f => new FileInfo(f).LastWriteTimeUtc)
-                    .Take(20)
+                    .Take(MaxFilesPerRun)
                     .ToList();
             }
             catch (Exception ex)
@@ -216,183 +234,248 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
         private static void ProcessLogFile(string filePath, GatherRule rule, Regex pattern,
             bool trackPosition, int maxLines, bool isTextMode, GatherRuleContext context)
         {
+            var fileName = Path.GetFileName(filePath);
             try
             {
-                var fileInfo = new FileInfo(filePath);
-                long startPosition = trackPosition
-                    ? context.FilePositionTracker.GetSafePosition(filePath, fileInfo.Length)
-                    : 0;
+                var state = context.SessionState;
+                var known = trackPosition ? state.PeekLogPosition(rule.RuleId, filePath) : null;
 
-                // Nothing new to read
-                if (startPosition >= fileInfo.Length)
+                // Nothing new since the last run — decided from the length alone, without opening the file.
+                var length = new FileInfo(filePath).Length;
+                if (known != null && known.Position == length)
                 {
                     context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
-                        $"{Path.GetFileName(filePath)}: no new content (position {startPosition} >= length {fileInfo.Length}) — trackPosition=true, nothing re-read");
+                        $"{fileName}: no new content (position {known.Position} >= length {length}) — trackPosition=true, nothing re-read" +
+                        (known.FromPreviousRun ? "; position saved by a previous agent run" : ""));
                     return;
                 }
 
+                // A last line without a line end is usually one its writer is still in. An interval
+                // rule leaves it for its next run, once. A one-shot trigger may have no next run, so it
+                // reads the line now but saves the position before it: the next run reads it again,
+                // whole — at worst a match repeats, it is never split.
+                var isInterval = string.Equals(rule.Trigger, "interval", StringComparison.OrdinalIgnoreCase);
+                var mayHoldTail = trackPosition && isInterval;
+                var tailReadAgainNextRun = false;
+
                 int matchCount = 0;
                 int linesRead = 0;
+                int committedLines = 0;
                 int parseFailCount = 0;
                 int timeoutCount = 0;
-                long endPosition = startPosition;
+                int oversizedCount = 0;
+                long startPosition;
+                long endPosition;
+                long lineNumberBase;
+                long fileLength;
+                long heldTailStart = -1;
+                LogFileHead head;
+                LogTextEncoding encoding;
 
                 using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
                 {
+                    fileLength = stream.Length;
+                    head = LogFileHead.Read(stream);
+                    encoding = head.Encoding;
+
+                    LogReadStart start;
+                    startPosition = encoding.AlignDown(GatherRuleSessionState.ResolveStart(known, fileLength, head, out start));
+                    lineNumberBase = start == LogReadStart.Continue ? known.LineNumber : 0;
+                    TraceReadStart(context, rule, fileName, known, start, fileLength);
+
                     stream.Seek(startPosition, SeekOrigin.Begin);
+                    var reader = new LogLineReader(stream, encoding, MaxLineBytes);
+                    endPosition = startPosition;
 
-                    using (var reader = new StreamReader(stream, Encoding.UTF8))
+                    while (linesRead < maxLines)
                     {
-                        string line;
-                        while ((line = reader.ReadLine()) != null && linesRead < maxLines)
+                        var line = reader.ReadLine();
+                        if (line == null)
                         {
-                            linesRead++;
-
-                            if (isTextMode)
-                            {
-                                // Text mode: match regex directly against the raw line
-                                Match match;
-                                try
-                                {
-                                    match = pattern.Match(line);
-                                }
-                                catch (RegexMatchTimeoutException)
-                                {
-                                    timeoutCount++;
-                                    continue;
-                                }
-                                if (!match.Success)
-                                    continue;
-
-                                var data = new Dictionary<string, object>();
-                                foreach (var groupName in pattern.GetGroupNames())
-                                {
-                                    if (groupName == "0") continue;
-                                    var group = match.Groups[groupName];
-                                    if (group.Success)
-                                        data[groupName] = group.Value;
-                                }
-
-                                data["logLine"] = TruncateMessage(line, 500);
-                                data["logLineNumber"] = linesRead;
-                                data["logFile"] = Path.GetFileName(filePath);
-                                data["ruleId"] = rule.RuleId;
-                                data["ruleTitle"] = rule.Title;
-                                GatherRuleExecutor.StampRuleMarkers(rule, data);
-
-                                var eventType = !string.IsNullOrEmpty(rule.OutputEventType)
-                                    ? rule.OutputEventType
-                                    : "logparser_match";
-                                var severity = GatherRuleContext.ParseSeverity(rule.OutputSeverity);
-
-                                context.OnEventCollected(new EnrollmentEvent
-                                {
-                                    SessionId = context.SessionId,
-                                    TenantId = context.TenantId,
-                                    Timestamp = DateTime.UtcNow,
-                                    EventType = eventType,
-                                    Severity = severity,
-                                    Source = GatherRuleExecutor.SourceName,
-                                    Message = $"Gather: {rule.Title}",
-                                    Data = data
-                                });
-
-                                matchCount++;
-                                TraceMatch(context, rule, Path.GetFileName(filePath), linesRead, match, pattern, matchCount);
-                            }
-                            else
-                            {
-                                // CMTrace mode: parse line as CMTrace format, match regex against message
-                                CmTraceLogEntry entry;
-                                if (!CmTraceLogParser.TryParseLine(line, out entry))
-                                {
-                                    parseFailCount++;
-                                    continue;
-                                }
-
-                                Match match;
-                                try
-                                {
-                                    match = pattern.Match(entry.Message);
-                                }
-                                catch (RegexMatchTimeoutException)
-                                {
-                                    timeoutCount++;
-                                    continue;
-                                }
-                                if (!match.Success)
-                                    continue;
-
-                                var data = new Dictionary<string, object>();
-                                foreach (var groupName in pattern.GetGroupNames())
-                                {
-                                    if (groupName == "0") continue;
-                                    var group = match.Groups[groupName];
-                                    if (group.Success)
-                                        data[groupName] = group.Value;
-                                }
-
-                                // Gather-rule logs are arbitrary files this collector does not
-                                // tail, so no writer offset can be measured for them; the
-                                // reader-zone fallback carries its known defect (see
-                                // ResolveUtcAssumingReaderZone). Behaviour unchanged from before
-                                // the parser split.
-                                var entryUtc = entry.TimestampUtc
-                                    ?? (entry.HasTimestamp
-                                        ? CmTraceLogParser.ResolveUtcAssumingReaderZone(entry.LocalTimestamp)
-                                        : DateTime.UtcNow);
-                                data["logTimestamp"] = entryUtc.ToString("o");
-                                data["logComponent"] = entry.Component;
-                                data["logType"] = entry.Type;
-                                data["logMessage"] = TruncateMessage(entry.Message, 500);
-                                data["logFile"] = Path.GetFileName(filePath);
-                                data["ruleId"] = rule.RuleId;
-                                data["ruleTitle"] = rule.Title;
-                                GatherRuleExecutor.StampRuleMarkers(rule, data);
-
-                                var eventType = !string.IsNullOrEmpty(rule.OutputEventType)
-                                    ? rule.OutputEventType
-                                    : "logparser_match";
-                                var severity = MapCmTraceTypeToSeverity(entry.Type, rule.OutputSeverity);
-
-                                context.OnEventCollected(new EnrollmentEvent
-                                {
-                                    SessionId = context.SessionId,
-                                    TenantId = context.TenantId,
-                                    Timestamp = entryUtc,
-                                    EventType = eventType,
-                                    Severity = severity,
-                                    Source = GatherRuleExecutor.SourceName,
-                                    Message = $"Gather: {rule.Title}",
-                                    Data = data
-                                });
-
-                                matchCount++;
-                                TraceMatch(context, rule, Path.GetFileName(filePath), linesRead, match, pattern, matchCount);
-                            }
+                            // End of file. A "\n" the reader skipped behind the "\r" the previous run
+                            // ended on is consumed too — unless a kept tail must be read again.
+                            if (!tailReadAgainNextRun)
+                                endPosition = reader.Position;
+                            break;
                         }
 
-                        // Capture the final stream position after reading
-                        endPosition = stream.Position;
+                        var unfinished = !reader.LastLineTerminated;
+                        if (unfinished && mayHoldTail
+                            && (known == null || known.HeldTailStart != reader.LastLineStart))
+                        {
+                            heldTailStart = reader.LastLineStart;
+                            break;
+                        }
+
+                        linesRead++;
+                        var lineNumber = lineNumberBase + linesRead;
+                        if (unfinished && trackPosition && !isInterval)
+                        {
+                            tailReadAgainNextRun = true;
+                        }
+                        else
+                        {
+                            endPosition = reader.Position;
+                            committedLines = linesRead;
+                        }
+
+                        if (reader.LastLineTruncated)
+                        {
+                            oversizedCount++;
+                            continue;
+                        }
+
+                        if (isTextMode)
+                        {
+                            // Text mode: match regex directly against the raw line
+                            Match match;
+                            try
+                            {
+                                match = pattern.Match(line);
+                            }
+                            catch (RegexMatchTimeoutException)
+                            {
+                                timeoutCount++;
+                                continue;
+                            }
+                            if (!match.Success)
+                                continue;
+
+                            var data = new Dictionary<string, object>();
+                            foreach (var groupName in pattern.GetGroupNames())
+                            {
+                                if (groupName == "0") continue;
+                                var group = match.Groups[groupName];
+                                if (group.Success)
+                                    data[groupName] = group.Value;
+                            }
+
+                            data["logLine"] = TruncateMessage(line, 500);
+                            data["logLineNumber"] = lineNumber;
+                            data["logFile"] = fileName;
+                            data["ruleId"] = rule.RuleId;
+                            data["ruleTitle"] = rule.Title;
+                            GatherRuleExecutor.StampRuleMarkers(rule, data);
+
+                            var eventType = !string.IsNullOrEmpty(rule.OutputEventType)
+                                ? rule.OutputEventType
+                                : "logparser_match";
+                            var severity = GatherRuleContext.ParseSeverity(rule.OutputSeverity);
+
+                            context.OnEventCollected(new EnrollmentEvent
+                            {
+                                SessionId = context.SessionId,
+                                TenantId = context.TenantId,
+                                Timestamp = DateTime.UtcNow,
+                                EventType = eventType,
+                                Severity = severity,
+                                Source = GatherRuleExecutor.SourceName,
+                                Message = $"Gather: {rule.Title}",
+                                Data = data
+                            });
+
+                            matchCount++;
+                            TraceMatch(context, rule, fileName, lineNumber, match, pattern, matchCount);
+                        }
+                        else
+                        {
+                            // CMTrace mode: parse line as CMTrace format, match regex against message
+                            CmTraceLogEntry entry;
+                            if (!CmTraceLogParser.TryParseLine(line, out entry))
+                            {
+                                parseFailCount++;
+                                continue;
+                            }
+
+                            Match match;
+                            try
+                            {
+                                match = pattern.Match(entry.Message);
+                            }
+                            catch (RegexMatchTimeoutException)
+                            {
+                                timeoutCount++;
+                                continue;
+                            }
+                            if (!match.Success)
+                                continue;
+
+                            var data = new Dictionary<string, object>();
+                            foreach (var groupName in pattern.GetGroupNames())
+                            {
+                                if (groupName == "0") continue;
+                                var group = match.Groups[groupName];
+                                if (group.Success)
+                                    data[groupName] = group.Value;
+                            }
+
+                            // Gather-rule logs are arbitrary files this collector does not
+                            // tail, so no writer offset can be measured for them; the
+                            // reader-zone fallback carries its known defect (see
+                            // ResolveUtcAssumingReaderZone). Behaviour unchanged from before
+                            // the parser split.
+                            var entryUtc = entry.TimestampUtc
+                                ?? (entry.HasTimestamp
+                                    ? CmTraceLogParser.ResolveUtcAssumingReaderZone(entry.LocalTimestamp)
+                                    : DateTime.UtcNow);
+                            data["logTimestamp"] = entryUtc.ToString("o");
+                            data["logComponent"] = entry.Component;
+                            data["logType"] = entry.Type;
+                            data["logMessage"] = TruncateMessage(entry.Message, 500);
+                            data["logFile"] = fileName;
+                            data["ruleId"] = rule.RuleId;
+                            data["ruleTitle"] = rule.Title;
+                            GatherRuleExecutor.StampRuleMarkers(rule, data);
+
+                            var eventType = !string.IsNullOrEmpty(rule.OutputEventType)
+                                ? rule.OutputEventType
+                                : "logparser_match";
+                            var severity = MapCmTraceTypeToSeverity(entry.Type, rule.OutputSeverity);
+
+                            context.OnEventCollected(new EnrollmentEvent
+                            {
+                                SessionId = context.SessionId,
+                                TenantId = context.TenantId,
+                                Timestamp = entryUtc,
+                                EventType = eventType,
+                                Severity = severity,
+                                Source = GatherRuleExecutor.SourceName,
+                                Message = $"Gather: {rule.Title}",
+                                Data = data
+                            });
+
+                            matchCount++;
+                            TraceMatch(context, rule, fileName, lineNumber, match, pattern, matchCount);
+                        }
                     }
                 }
 
+                // Saved only now, after every event of this file went out: a process that dies
+                // before this line repeats the file's new lines after the restart, never skips them.
                 if (trackPosition)
-                    context.FilePositionTracker.SetPosition(filePath, endPosition);
+                    state.CommitLogPosition(rule.RuleId, filePath, endPosition, lineNumberBase + committedLines, head, heldTailStart);
 
                 if (matchCount > 0)
-                    context.Logger.Debug($"LogParser rule {rule.RuleId}: {matchCount} matches from {linesRead} lines in {Path.GetFileName(filePath)}");
+                    context.Logger.Debug($"LogParser rule {rule.RuleId}: {matchCount} matches from {linesRead} lines in {fileName}");
 
                 // Per-file outcome — always written so a "matched 0" run is visible too.
                 context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
-                    $"{Path.GetFileName(filePath)}: read {linesRead} lines from position {startPosition}->{endPosition}, " +
-                    $"matched {matchCount}, parseFailures={parseFailCount}, regexTimeouts={timeoutCount}, mode={(isTextMode ? "text" : "cmtrace")}");
+                    $"{fileName}: read {linesRead} lines from position {startPosition}->{endPosition}, " +
+                    $"matched {matchCount}, parseFailures={parseFailCount}, regexTimeouts={timeoutCount}, mode={(isTextMode ? "text" : "cmtrace")}, encoding={encoding.Name}" +
+                    (oversizedCount > 0 ? $", skipped {oversizedCount} line(s) over {MaxLineBytes / (1024 * 1024)} MB" : ""));
+
+                if (heldTailStart >= 0)
+                    context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                        $"{fileName}: last line has no line end yet — left for the next run, read then even if still unfinished");
+                else if (tailReadAgainNextRun)
+                    context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                        $"{fileName}: last line has no line end yet — read now and again by the next run, position kept before it");
 
                 if (!isTextMode && linesRead > 0 && parseFailCount == linesRead)
                     context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
                         "every line failed CMTrace parsing — if this is a plain-text log, set parameter format=text");
 
-                if (linesRead == maxLines)
+                if (linesRead == maxLines && endPosition < fileLength)
                     context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
                         $"stopped at maxLines={maxLines} — remaining content is deferred to the next run");
             }
@@ -403,6 +486,27 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             }
         }
 
+        private static void TraceReadStart(GatherRuleContext context, GatherRule rule, string fileName,
+            LogPositionSnapshot known, LogReadStart start, long fileLength)
+        {
+            if (start == LogReadStart.Shrunk)
+            {
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                    $"{fileName}: file is shorter than the saved position (length {fileLength} < {known.Position}) — truncated or recreated, reading from the beginning");
+            }
+            else if (start == LogReadStart.Replaced)
+            {
+                context.Logger.Info($"LogParser rule {rule.RuleId}: {fileName} was replaced since the last read — reading it from the beginning");
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                    $"{fileName}: file start changed since the last read (replaced or rewritten) — saved position {known.Position} discarded, reading from the beginning");
+            }
+            else if (start == LogReadStart.Continue && known.FromPreviousRun)
+            {
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                    $"{fileName}: continuing at position {known.Position} (after line {known.LineNumber}) saved by a previous agent run");
+            }
+        }
+
         private static EventSeverity MapCmTraceTypeToSeverity(int cmTraceType, string ruleOverride)
         {
             // If the rule specifies a severity, use it

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/Collectors/XmlCollector.cs

@@ -26,7 +26,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             // Expand custom tokens (%LOGGED_ON_USER_PROFILE%) and standard environment variables
             var userProfilePath = UserProfileResolver.ContainsUserProfileToken(filePath)
                 ? UserProfileResolver.GetLoggedOnUserProfilePath() : null;
-            filePath = UserProfileResolver.ExpandCustomTokens(filePath);
+            filePath = UserProfileResolver.ExpandCustomTokens(filePath, userProfilePath);
             if (filePath == null)
                 return data; // Token present but no user logged on — skip silently
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleContext.cs

@@ -4,7 +4,6 @@ using AutopilotMonitor.Agent.V2.Core.Logging;
 using AutopilotMonitor.Shared;
 using AutopilotMonitor.Shared.Models;
 using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment;
-using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
 using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
 
 namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
@@ -19,7 +18,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
         public string TenantId { get; }
         public Action<EnrollmentEvent> OnEventCollected { get; }
         public string ImeLogPathOverride { get; }
-        public LogFilePositionTracker FilePositionTracker { get; }
+
+        /// <summary>Logparser positions per (rule, file) and on_change values; survives agent restarts when persisted.</summary>
+        public GatherRuleSessionState SessionState { get; }
+
         public bool UnrestrictedMode { get; set; }
 
         /// <summary>
@@ -34,7 +36,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             string tenantId,
             Action<EnrollmentEvent> onEventCollected,
             string imeLogPathOverride,
-            LogFilePositionTracker filePositionTracker,
+            GatherRuleSessionState sessionState,
             GatherRuleDebugLog debugLog = null)
         {
             Logger = logger ?? throw new ArgumentNullException(nameof(logger));
@@ -42,7 +44,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             TenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
             OnEventCollected = onEventCollected ?? throw new ArgumentNullException(nameof(onEventCollected));
             ImeLogPathOverride = imeLogPathOverride;
-            FilePositionTracker = filePositionTracker ?? throw new ArgumentNullException(nameof(filePositionTracker));
+            SessionState = sessionState ?? throw new ArgumentNullException(nameof(sessionState));
             DebugWriter = debugLog;
         }
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleExecutor.cs

@@ -10,7 +10,6 @@ using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors;
 using AutopilotMonitor.Shared;
 using AutopilotMonitor.Shared.Models;
 using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment;
-using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
 using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
 
 namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
@@ -38,6 +37,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
 
         private readonly AgentLogger _logger;
         private readonly GatherRuleDebugLog _debug;   // null unless EnableGatherRuleDebugLog / --gather-debug-log
+        private readonly GatherRuleSessionState _state;
         private readonly GatherRuleContext _context;
         private readonly Dictionary<string, IGatherRuleCollector> _collectors;
 
@@ -50,12 +50,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
 
         // Phase-scope + emit-mode state (ActivePhases / ActiveFromPhase / EmitMode on GatherRule).
         // Guarded by _scopeLock; collector work always runs outside the lock. The state deliberately
-        // survives UpdateRules config refreshes — an agent restart causes at most one re-emit per
-        // on_change rule (acceptable under the per-enrollment lifecycle).
+        // survives UpdateRules config refreshes. Across agent restarts only the last emitted hash
+        // survives: it is seeded from _state and committed there after each emit, so an unchanged
+        // on_change result stays silent after a reboot. Phase latches, dedup sets and the
+        // suppression streak are process-scoped.
         private readonly object _scopeLock = new object();
         private EnrollmentPhase _currentPhase = EnrollmentPhase.Unknown;
         private readonly HashSet<string> _fromPhaseLatched = new HashSet<string>();
         private readonly Dictionary<string, string> _lastEmittedHash = new Dictionary<string, string>();
+        private readonly HashSet<string> _hashFromPreviousRun = new HashSet<string>();
         private readonly Dictionary<string, (int Count, DateTime SinceUtc)> _suppressed =
             new Dictionary<string, (int Count, DateTime SinceUtc)>();
         private readonly HashSet<string> _scopeBypassLogged = new HashSet<string>();
@@ -77,9 +80,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             set { _context.UnrestrictedMode = value; }
         }
 
+        /// <param name="stateDirectory">
+        /// Where logparser positions and on_change values are kept across agent restarts. Null keeps
+        /// them in memory — required for <c>--run-gather-rules</c>, which runs beside the live agent
+        /// under a throwaway session id and must not overwrite the session's file.
+        /// </param>
         public GatherRuleExecutor(string sessionId, string tenantId, Action<EnrollmentEvent> onEventCollected,
             AgentLogger logger, string imeLogPathOverride = null, string debugLogPath = null,
-            Action<string> debugEcho = null)
+            Action<string> debugEcho = null, string stateDirectory = null)
         {
             if (sessionId == null) throw new ArgumentNullException(nameof(sessionId));
             if (tenantId == null) throw new ArgumentNullException(nameof(tenantId));
@@ -89,8 +97,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             _logger = logger;
             _debug = string.IsNullOrEmpty(debugLogPath) ? null : new GatherRuleDebugLog(debugLogPath, logger, debugEcho);
 
-            var filePositionTracker = new LogFilePositionTracker();
-            _context = new GatherRuleContext(logger, sessionId, tenantId, onEventCollected, imeLogPathOverride, filePositionTracker, _debug);
+            var persistence = string.IsNullOrEmpty(stateDirectory) ? null : new GatherRuleStatePersistence(stateDirectory, logger);
+            _state = new GatherRuleSessionState(sessionId, persistence, logger);
+            _context = new GatherRuleContext(logger, sessionId, tenantId, onEventCollected, imeLogPathOverride, _state, _debug);
+
+            foreach (var hash in _state.GetEmittedHashes())
+            {
+                _lastEmittedHash[hash.Key] = hash.Value;
+                _hashFromPreviousRun.Add(hash.Key);
+            }
+            _logger.Info($"GatherRuleExecutor: gather state {_state.RestoreSummary}");
+            DebugLog(null, GatherRuleDebugLog.StageConfig, $"gather state: {_state.RestoreSummary}");
+            foreach (var detail in _state.RestoredDetails)
+                DebugLog(detail.Key, GatherRuleDebugLog.StageConfig, detail.Value);
 
             // Register all collector strategies
             var collectorList = new IGatherRuleCollector[]
@@ -480,14 +499,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                     // empty result never reaches this point, so an emitOnlyIfExists miss neither
                     // emits nor updates the hash — composing to "one event on appearance, then
                     // only on change".
+                    string emittedHash = null;
                     if (IsOnChangeMode(rule))
                     {
                         string hashPrefix;
                         int suppressedStreak;
-                        if (!ShouldEmitOnChange(rule, result, out hashPrefix, out suppressedStreak))
+                        bool comparedWithPreviousRun;
+                        if (!ShouldEmitOnChange(rule, result, out emittedHash, out hashPrefix, out suppressedStreak, out comparedWithPreviousRun))
                         {
                             DebugLog(rule.RuleId, GatherRuleDebugLog.StageSuppress,
-                                $"result unchanged (hash {hashPrefix}) — emit suppressed (on_change), suppressed streak={suppressedStreak}");
+                                $"result unchanged (hash {hashPrefix}) — emit suppressed (on_change), suppressed streak={suppressedStreak}" +
+                                (comparedWithPreviousRun ? "; compared with the value a previous agent run emitted" : ""));
                             return;
                         }
                         DebugLog(rule.RuleId, GatherRuleDebugLog.StageEmit,
@@ -524,6 +546,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                         Message = $"Gather: {rule.Title}",
                         Data = result
                     });
+
+                    // Committed only after the event went out: a process that dies in between emits
+                    // the result once more after the restart instead of never.
+                    if (emittedHash != null)
+                        _state.CommitEmittedHash(rule.RuleId, emittedHash);
+
                     DebugLog(rule.RuleId, GatherRuleDebugLog.StageEmit,
                         $"emitted {eventType} (severity={severity}, {result.Count} fields)");
                 }
@@ -679,9 +707,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
         internal bool ShouldEmitOnChange(GatherRule rule, Dictionary<string, object> result,
             out string hashPrefix, out int suppressedStreak)
         {
-            var hash = ComputeCanonicalHash(result);
+            string hash;
+            bool comparedWithPreviousRun;
+            return ShouldEmitOnChange(rule, result, out hash, out hashPrefix, out suppressedStreak, out comparedWithPreviousRun);
+        }
+
+        /// <summary>
+        /// Full form: <paramref name="hash"/> is the result's canonical hash, committed to the session
+        /// state once the event went out; <paramref name="comparedWithPreviousRun"/> says a suppression
+        /// compared against the value a previous agent run emitted.
+        /// </summary>
+        private bool ShouldEmitOnChange(GatherRule rule, Dictionary<string, object> result,
+            out string hash, out string hashPrefix, out int suppressedStreak, out bool comparedWithPreviousRun)
+        {
+            hash = ComputeCanonicalHash(result);
             hashPrefix = hash.Length > 8 ? hash.Substring(0, 8) : hash;
             suppressedStreak = 0;
+            comparedWithPreviousRun = false;
             bool emit;
             lock (_scopeLock)
             {
@@ -693,11 +735,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                         ? (streak.Count + 1, streak.SinceUtc)
                         : (1, DateTime.UtcNow);
                     suppressedStreak = _suppressed[rule.RuleId].Count;
+                    comparedWithPreviousRun = _hashFromPreviousRun.Contains(rule.RuleId);
                     emit = false;
                 }
                 else
                 {
                     _lastEmittedHash[rule.RuleId] = hash;
+                    _hashFromPreviousRun.Remove(rule.RuleId);
                     (int Count, DateTime SinceUtc) streak;
                     if (_suppressed.TryGetValue(rule.RuleId, out streak) && streak.Count > 0)
                     {
@@ -820,6 +864,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             StopAllTimers();
             _startupRulesLatch?.Dispose();
             _startupRulesLatch = null;
+            // A rule still finishing on a pool thread keeps its in-memory state but no longer writes:
+            // the agent may be removing its own folder right now.
+            _state.Close();
         }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleSessionState.cs

@@ -0,0 +1,399 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
+{
+    /// <summary>
+    /// Gather-rule state of one enrollment session that survives agent restarts: where each
+    /// logparser rule stopped reading each file, and the on_change value each rule last emitted.
+    /// <para>
+    /// Positions are kept per (rule, file) — two rules parsing the same log each read all of it.
+    /// Every position carries a fingerprint of the file's first bytes, so a file replaced under
+    /// the same name is read from the beginning even when it is already longer than the position.
+    /// </para>
+    /// <para>
+    /// Every commit is written to disk synchronously, AFTER the events it covers were handed on:
+    /// a process that dies in between repeats that one pass after the restart instead of losing it.
+    /// The lock guards memory and file write together and is never taken under the executor's
+    /// scope lock. Without a persistence (diagnostic mode, tests) the state lives in memory only.
+    /// </para>
+    /// </summary>
+    public sealed class GatherRuleSessionState
+    {
+        /// <summary>
+        /// Files remembered per rule. A run reads at most <see cref="LogParserCollector.MaxFilesPerRun"/>
+        /// files; the least recently touched entry beyond the cap is dropped, and its file — should it
+        /// come back — is simply read again.
+        /// </summary>
+        internal const int MaxLogFilesPerRule = 5 * LogParserCollector.MaxFilesPerRun;
+
+        private static readonly char[] WildcardChars = { '*', '?' };
+
+        private readonly object _gate = new object();
+        private readonly string _sessionId;
+        private readonly GatherRuleStatePersistence _persistence;
+        private readonly AgentLogger _logger;
+        private readonly Dictionary<string, Dictionary<string, Entry>> _logPositions =
+            new Dictionary<string, Dictionary<string, Entry>>(StringComparer.Ordinal);
+        private readonly Dictionary<string, string> _emittedHashes = new Dictionary<string, string>(StringComparer.Ordinal);
+        private readonly List<KeyValuePair<string, string>> _restoredDetails = new List<KeyValuePair<string, string>>();
+        private long _touchCounter;
+        private bool _unsaved;
+        private bool _saveFailureLogged;
+        private bool _closed;
+
+        private sealed class Entry
+        {
+            public long Position;
+            public long LineNumber;
+            public int HeadLength;
+            public string HeadHash;
+            public bool FromPreviousRun;
+            public long HeldTailStart = -1;
+            public long LastTouched;
+        }
+
+        public GatherRuleSessionState(string sessionId, GatherRuleStatePersistence persistence, AgentLogger logger)
+        {
+            _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _persistence = persistence;
+            RestoreSummary = Restore();
+        }
+
+        /// <summary>One line on what the constructor found on disk — for the agent log and the debug trace.</summary>
+        public string RestoreSummary { get; }
+
+        /// <summary>(ruleId, message) per restored position and on_change value — for the debug trace.</summary>
+        internal IReadOnlyList<KeyValuePair<string, string>> RestoredDetails => _restoredDetails;
+
+        // ===== logparser positions =====
+
+        /// <summary>The recorded position of <paramref name="filePath"/> for the rule, or null when it has none.</summary>
+        internal LogPositionSnapshot PeekLogPosition(string ruleId, string filePath)
+        {
+            lock (_gate)
+            {
+                Dictionary<string, Entry> files;
+                Entry entry;
+                if (!_logPositions.TryGetValue(ruleId, out files) || !files.TryGetValue(filePath, out entry))
+                    return null;
+                entry.LastTouched = ++_touchCounter;
+                return new LogPositionSnapshot(entry.Position, entry.LineNumber, entry.HeadLength, entry.HeadHash,
+                    entry.FromPreviousRun, entry.HeldTailStart);
+            }
+        }
+
+        /// <summary>
+        /// Records where the rule stopped in the file and saves the state when it changed.
+        /// <paramref name="heldTailStart"/> (in memory only) marks an unfinished last line left for
+        /// the next run; -1 when none.
+        /// </summary>
+        internal void CommitLogPosition(string ruleId, string filePath, long position, long lineNumber,
+            LogFileHead head, long heldTailStart)
+        {
+            var headLength = head.Length;
+            var headHash = headLength > 0 ? head.Hash(headLength) : null;
+
+            lock (_gate)
+            {
+                Dictionary<string, Entry> files;
+                if (!_logPositions.TryGetValue(ruleId, out files))
+                {
+                    files = new Dictionary<string, Entry>(StringComparer.OrdinalIgnoreCase);
+                    _logPositions[ruleId] = files;
+                }
+
+                Entry entry;
+                var changed = false;
+                if (!files.TryGetValue(filePath, out entry))
+                {
+                    entry = new Entry();
+                    files[filePath] = entry;
+                    changed = true;
+                }
+
+                if (changed || entry.Position != position || entry.LineNumber != lineNumber
+                    || entry.HeadLength != headLength || !string.Equals(entry.HeadHash, headHash, StringComparison.Ordinal))
+                {
+                    entry.Position = position;
+                    entry.LineNumber = lineNumber;
+                    entry.HeadLength = headLength;
+                    entry.HeadHash = headHash;
+                    entry.FromPreviousRun = false;
+                    changed = true;
+                }
+                entry.HeldTailStart = heldTailStart;
+                entry.LastTouched = ++_touchCounter;
+
+                if (files.Count > MaxLogFilesPerRule)
+                    EvictLeastRecentlyTouched(ruleId, files);
+
+                if (changed || _unsaved)
+                    SaveLocked();
+            }
+        }
+
+        /// <summary>
+        /// Where to continue reading: the recorded position while the file is still the one it was
+        /// recorded for, otherwise 0 with the reason.
+        /// </summary>
+        internal static long ResolveStart(LogPositionSnapshot known, long fileLength, LogFileHead head, out LogReadStart start)
+        {
+            if (known == null)
+            {
+                start = LogReadStart.FirstRead;
+                return 0;
+            }
+            if (fileLength < known.Position)
+            {
+                start = LogReadStart.Shrunk;
+                return 0;
+            }
+            if (known.HeadLength > 0
+                && (head.Length < known.HeadLength
+                    || !string.Equals(head.Hash(known.HeadLength), known.HeadHash, StringComparison.Ordinal)))
+            {
+                start = LogReadStart.Replaced;
+                return 0;
+            }
+            start = LogReadStart.Continue;
+            return known.Position;
+        }
+
+        // ===== on_change values =====
+
+        /// <summary>Rule id → hash of the result the rule last emitted.</summary>
+        internal Dictionary<string, string> GetEmittedHashes()
+        {
+            lock (_gate)
+                return new Dictionary<string, string>(_emittedHashes, StringComparer.Ordinal);
+        }
+
+        /// <summary>Records the hash of a result that was just emitted and saves the state when it changed.</summary>
+        internal void CommitEmittedHash(string ruleId, string hash)
+        {
+            lock (_gate)
+            {
+                string current;
+                var changed = !_emittedHashes.TryGetValue(ruleId, out current)
+                              || !string.Equals(current, hash, StringComparison.Ordinal);
+                _emittedHashes[ruleId] = hash;
+                if (changed || _unsaved)
+                    SaveLocked();
+            }
+        }
+
+        /// <summary>Retries a save that failed earlier, then stops writing (executor disposed).</summary>
+        internal void Close()
+        {
+            lock (_gate)
+            {
+                if (_unsaved)
+                    SaveLocked();
+                _closed = true;
+            }
+        }
+
+        // ===== persistence =====
+
+        private void SaveLocked()
+        {
+            if (_persistence == null || _closed)
+            {
+                _unsaved = false;
+                return;
+            }
+
+            var data = new GatherRuleStateData
+            {
+                SessionId = _sessionId,
+                SavedAtUtc = DateTime.UtcNow,
+                LogPositions = _logPositions
+                    .SelectMany(rule => rule.Value.Select(file => new { RuleId = rule.Key, Path = file.Key, Entry = file.Value }))
+                    .OrderBy(x => x.Entry.LastTouched)
+                    .Select(x => new GatherLogPositionData
+                    {
+                        RuleId = x.RuleId,
+                        Path = x.Path,
+                        Position = x.Entry.Position,
+                        LineNumber = x.Entry.LineNumber,
+                        HeadLength = x.Entry.HeadLength,
+                        HeadHash = x.Entry.HeadHash,
+                    })
+                    .ToList(),
+                OnChangeHashes = new Dictionary<string, string>(_emittedHashes, StringComparer.Ordinal),
+            };
+
+            if (_persistence.Save(data))
+            {
+                _unsaved = false;
+                _saveFailureLogged = false;
+                return;
+            }
+
+            _unsaved = true;
+            if (!_saveFailureLogged)
+            {
+                _saveFailureLogged = true;
+                _logger.Warning($"GatherRuleSessionState: saving {_persistence.StateFilePath} failed — kept in memory, retried at the next change");
+            }
+        }
+
+        private string Restore()
+        {
+            if (_persistence == null)
+                return "persistence off (no state directory) — positions and on_change values live in memory only";
+
+            string discardReason;
+            var data = _persistence.Load(_sessionId, out discardReason);
+            if (data == null)
+            {
+                return discardReason == null
+                    ? "no saved state — first agent run of this session"
+                    : $"saved state discarded ({discardReason}) — starting fresh";
+            }
+
+            // The file is input like any other: whatever it holds, the executor must come up. A
+            // failure here would otherwise stop every collector host, at every restart of the session.
+            try
+            {
+                return RestoreFrom(data);
+            }
+            catch (Exception ex)
+            {
+                _logPositions.Clear();
+                _emittedHashes.Clear();
+                _restoredDetails.Clear();
+                _logger.Warning($"GatherRuleSessionState: restoring {_persistence.StateFilePath} failed, starting fresh: {ex.Message}");
+                return $"saved state discarded (restore failed: {ex.Message}) — starting fresh";
+            }
+        }
+
+        private string RestoreFrom(GatherRuleStateData data)
+        {
+            var dropped = 0;
+            foreach (var position in data.LogPositions ?? new List<GatherLogPositionData>())
+            {
+                if (!IsValid(position))
+                {
+                    dropped++;
+                    continue;
+                }
+
+                Dictionary<string, Entry> files;
+                if (!_logPositions.TryGetValue(position.RuleId, out files))
+                {
+                    files = new Dictionary<string, Entry>(StringComparer.OrdinalIgnoreCase);
+                    _logPositions[position.RuleId] = files;
+                }
+                files[position.Path] = new Entry
+                {
+                    Position = position.Position,
+                    LineNumber = position.LineNumber,
+                    HeadLength = position.HeadLength,
+                    HeadHash = position.HeadLength > 0 ? position.HeadHash : null,
+                    FromPreviousRun = true,
+                    LastTouched = ++_touchCounter,
+                };
+                if (files.Count > MaxLogFilesPerRule)
+                    EvictLeastRecentlyTouched(position.RuleId, files);
+            }
+
+            foreach (var hash in data.OnChangeHashes ?? new Dictionary<string, string>())
+            {
+                if (string.IsNullOrEmpty(hash.Key) || string.IsNullOrEmpty(hash.Value))
+                {
+                    dropped++;
+                    continue;
+                }
+                _emittedHashes[hash.Key] = hash.Value;
+            }
+
+            foreach (var rule in _logPositions)
+            {
+                foreach (var file in rule.Value)
+                {
+                    _restoredDetails.Add(new KeyValuePair<string, string>(rule.Key,
+                        $"logparser position restored: {Path.GetFileName(file.Key)} at byte {file.Value.Position}, after line {file.Value.LineNumber}"));
+                }
+            }
+            foreach (var hash in _emittedHashes)
+            {
+                _restoredDetails.Add(new KeyValuePair<string, string>(hash.Key,
+                    $"on_change value restored (hash {Prefix(hash.Value)}) — an unchanged result stays silent"));
+            }
+
+            var positionCount = _logPositions.Sum(rule => rule.Value.Count);
+            return $"restored {positionCount} logparser position(s) for {_logPositions.Count} rule(s) and {_emittedHashes.Count} on_change value(s), " +
+                   $"saved {data.SavedAtUtc:yyyy-MM-ddTHH:mm:ssZ} by a previous agent run of this session" +
+                   (dropped > 0 ? $"; {dropped} invalid entr{(dropped == 1 ? "y" : "ies")} dropped" : "") +
+                   " — logparser rules continue after their saved position, on_change rules stay silent until their result changes";
+        }
+
+        private static bool IsValid(GatherLogPositionData position)
+        {
+            if (position == null || string.IsNullOrEmpty(position.RuleId) || string.IsNullOrEmpty(position.Path))
+                return false;
+            // A real resolved path never carries these; Path APIs throw on them under .NET Framework.
+            if (position.Path.IndexOfAny(Path.GetInvalidPathChars()) >= 0 || position.Path.IndexOfAny(WildcardChars) >= 0)
+                return false;
+            if (position.Position < 0 || position.LineNumber < 0)
+                return false;
+            if (position.HeadLength < 0 || position.HeadLength > LogFileHead.MaxBytes)
+                return false;
+            if (position.HeadLength > 0 && string.IsNullOrEmpty(position.HeadHash))
+                return false;
+            // Reading any byte records a non-empty head; a position without one cannot be verified.
+            return position.Position == 0 || position.HeadLength > 0;
+        }
+
+        private void EvictLeastRecentlyTouched(string ruleId, Dictionary<string, Entry> files)
+        {
+            var oldest = files.OrderBy(file => file.Value.LastTouched).First();
+            files.Remove(oldest.Key);
+            _logger.Info($"GatherRuleSessionState: rule {ruleId} tracks more than {MaxLogFilesPerRule} files — forgot the position of {Path.GetFileName(oldest.Key)}");
+        }
+
+        private static string Prefix(string hash) => hash.Length > 8 ? hash.Substring(0, 8) : hash;
+    }
+
+    /// <summary>Immutable copy of a recorded logparser position.</summary>
+    internal sealed class LogPositionSnapshot
+    {
+        public LogPositionSnapshot(long position, long lineNumber, int headLength, string headHash,
+            bool fromPreviousRun, long heldTailStart)
+        {
+            Position = position;
+            LineNumber = lineNumber;
+            HeadLength = headLength;
+            HeadHash = headHash;
+            FromPreviousRun = fromPreviousRun;
+            HeldTailStart = heldTailStart;
+        }
+
+        public long Position { get; }
+        public long LineNumber { get; }
+        public int HeadLength { get; }
+        public string HeadHash { get; }
+
+        /// <summary>Restored from disk and not advanced by this process yet.</summary>
+        public bool FromPreviousRun { get; }
+
+        /// <summary>Start of an unfinished last line left for this run by the previous one; -1 when none.</summary>
+        public long HeldTailStart { get; }
+    }
+
+    /// <summary>How <see cref="GatherRuleSessionState.ResolveStart"/> decided where reading starts.</summary>
+    internal enum LogReadStart
+    {
+        FirstRead,
+        Continue,
+        Shrunk,
+        Replaced,
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleStatePersistence.cs

@@ -0,0 +1,131 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using Newtonsoft.Json;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
+{
+    /// <summary>
+    /// Persists <see cref="GatherRuleSessionState"/> in the agent's state directory so one
+    /// enrollment's logparser positions and on_change values survive agent restarts, reboots and
+    /// the WhiteGlove Part 2 resume.
+    /// <para>
+    /// The state is only resumed for the SAME session id: the state directory is one fixed folder
+    /// that a session rotation does not clear, and the new session starts empty in the backend, so
+    /// it must read its logs from the beginning.
+    /// </para>
+    /// Fail-soft like <c>BandwidthStatePersistence</c>: I/O errors never throw; a missing, corrupt
+    /// or foreign file loads as null (fresh start — the pre-persistence behavior).
+    /// </summary>
+    public class GatherRuleStatePersistence
+    {
+        public const string FileName = "gather-rule-state.json";
+
+        private const string SourceName = "GatherRuleStatePersistence";
+
+        private readonly string _stateDirectory;
+        private readonly string _stateFilePath;
+        private readonly AgentLogger _logger;
+
+        public GatherRuleStatePersistence(string stateDirectory, AgentLogger logger)
+        {
+            _stateDirectory = Environment.ExpandEnvironmentVariables(stateDirectory);
+            _stateFilePath = Path.Combine(_stateDirectory, FileName);
+            _logger = logger;
+        }
+
+        public string StateFilePath => _stateFilePath;
+
+        /// <summary>
+        /// Loads the persisted state, or null when absent, unreadable, or written for a different
+        /// session. <paramref name="discardReason"/> is null when there simply was no file.
+        /// </summary>
+        public GatherRuleStateData Load(string expectedSessionId, out string discardReason)
+        {
+            discardReason = null;
+            if (!File.Exists(_stateFilePath)) return null;
+            try
+            {
+                var json = File.ReadAllText(_stateFilePath);
+                var state = JsonConvert.DeserializeObject<GatherRuleStateData>(json);
+                if (state == null || string.IsNullOrEmpty(state.SessionId))
+                {
+                    discardReason = "state file empty or invalid";
+                    _logger.Warning($"[{SourceName}] persisted state file was empty or invalid — starting fresh");
+                    return null;
+                }
+                if (!string.Equals(state.SessionId, expectedSessionId, StringComparison.OrdinalIgnoreCase))
+                {
+                    discardReason = $"saved for session {state.SessionId}, current session is {expectedSessionId}";
+                    _logger.Warning($"[{SourceName}] persisted state belongs to session {state.SessionId}, not {expectedSessionId} — starting fresh");
+                    return null;
+                }
+                return state;
+            }
+            catch (Exception ex)
+            {
+                discardReason = $"state file unreadable: {ex.Message}";
+                _logger.Warning($"[{SourceName}] failed to load persisted state, starting fresh: {ex.Message}");
+                return null;
+            }
+        }
+
+        /// <summary>Persists the state (atomic write via temp file). Never throws; false when the write failed.</summary>
+        public bool Save(GatherRuleStateData state)
+        {
+            try
+            {
+                Directory.CreateDirectory(_stateDirectory);
+                var tempPath = _stateFilePath + ".tmp";
+                File.WriteAllText(tempPath, JsonConvert.SerializeObject(state));
+                if (File.Exists(_stateFilePath))
+                {
+                    File.Replace(tempPath, _stateFilePath, destinationBackupFileName: null, ignoreMetadataErrors: true);
+                }
+                else
+                {
+                    File.Move(tempPath, _stateFilePath);
+                }
+                return true;
+            }
+            catch (Exception ex)
+            {
+                _logger.Debug($"[{SourceName}] failed to save state: {ex.Message}");
+                return false;
+            }
+        }
+    }
+
+    // ---- DTOs for state serialization ----
+
+    public class GatherRuleStateData
+    {
+        public string SessionId { get; set; }
+        public DateTime SavedAtUtc { get; set; }
+
+        /// <summary>Least recently used first, so a restore keeps the eviction order.</summary>
+        public List<GatherLogPositionData> LogPositions { get; set; }
+
+        /// <summary>Rule id → canonical hash of the result the rule last emitted (on_change).</summary>
+        public Dictionary<string, string> OnChangeHashes { get; set; }
+    }
+
+    public class GatherLogPositionData
+    {
+        public string RuleId { get; set; }
+        public string Path { get; set; }
+
+        /// <summary>File offset right behind the last line the rule processed.</summary>
+        public long Position { get; set; }
+
+        /// <summary>Lines before <see cref="Position"/> — the base for <c>logLineNumber</c>.</summary>
+        public long LineNumber { get; set; }
+
+        /// <summary>Bytes from the start of the file the fingerprint covers (0..4096).</summary>
+        public int HeadLength { get; set; }
+
+        /// <summary>SHA-256 of those bytes, Base64; null when <see cref="HeadLength"/> is 0.</summary>
+        public string HeadHash { get; set; }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Periodic/AgentSelfMetricsCollector.cs

@@ -215,6 +215,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
                         data["ime_verified_bytes"] = health.VerifiedBytes;
                         data["ime_pass_max_ms"] = health.PassMaxMs;
                         data["ime_pass_gap_max_ms"] = health.PassGapMaxMs;
+                        data["ime_platform_output_verified"] = health.PlatformOutputVerified;
+                        data["ime_platform_output_corrected"] = health.PlatformOutputCorrected;
                     }
                 }
                 catch (Exception ex)

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Transport/BackendApiClient.cs

@@ -237,6 +237,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Transport
                 using (response)
                 {
                     await ThrowOnAuthFailureAsync(response).ConfigureAwait(false);
+                    await ThrowOnCodedConflictAsync(response).ConfigureAwait(false);
                     response.EnsureSuccessStatusCode();
 
                     var responseJson = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
@@ -338,6 +339,38 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Transport
                 errorCode: errorCode);
         }
 
+        /// <summary>
+        /// Throws <see cref="BackendRefusalException"/> for a 409 whose JSON body carries a
+        /// machine-readable <c>errorCode</c> — register-session answers
+        /// <c>session_owner_mismatch</c> when another tenant claimed the session id, which no retry
+        /// can clear but a session rotation can. A 409 without a code falls through to
+        /// <c>EnsureSuccessStatusCode</c> as before.
+        /// </summary>
+        private static async Task ThrowOnCodedConflictAsync(HttpResponseMessage response)
+        {
+            if (response.StatusCode != System.Net.HttpStatusCode.Conflict)
+                return;
+
+            string body = null;
+            try
+            {
+                body = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
+            }
+            catch
+            {
+                // No body, no code — the generic 409 handling applies.
+            }
+
+            var errorCode = TryExtractErrorCode(body);
+            if (errorCode == null)
+                return;
+
+            throw new BackendRefusalException(
+                $"Backend returned 409 Conflict with error code {errorCode}.",
+                (int)response.StatusCode,
+                errorCode);
+        }
+
         /// <summary>
         /// Pulls <c>errorCode</c> out of a backend JSON error body. Tolerant: any parse failure
         /// or a non-string value yields null, never an exception.
@@ -471,4 +504,24 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Transport
             ErrorCode = errorCode;
         }
     }
+
+    /// <summary>
+    /// Thrown when the backend refuses a request on a non-auth status (409) with a machine-readable
+    /// code from Shared <c>Constants.AgentErrorCodes</c>. Unlike <see cref="BackendAuthException"/>
+    /// it says nothing about the device's authorization and must never feed the auth-failure tracker.
+    /// </summary>
+    public class BackendRefusalException : Exception
+    {
+        /// <summary>HTTP status code returned by the backend (409).</summary>
+        public int StatusCode { get; }
+
+        /// <summary>Machine-readable code from the backend's JSON body (never null).</summary>
+        public string ErrorCode { get; }
+
+        public BackendRefusalException(string message, int statusCode, string errorCode) : base(message)
+        {
+            StatusCode = statusCode;
+            ErrorCode = errorCode;
+        }
+    }
 }